Tickets were once mementos — physical items soaked in memories and nostalgia, tucked away in attics and scrapbooks. They are now barcodes on our phones.

By the numbers: 98% of NFL fans used mobile tickets during preseason games this summer, according to the league. That's up from 67% in 2019.

• 67% of transactions on ticket marketplace SeatGeek in 2021 have been made on mobile, per the company. That's up from 7% in 2012.
• Of note: SeatGeek's numbers represent the percentage of purchases made, not the percentage of people who used their phones to scan into events, which is likely much higher.

The state of play: 85% of Americans own a smartphone, up from 35% in 2011, so this shift was inevitable. The pandemic only sped up the process, with most leagues going mobile-only to limit physical contact.

The big picture: The benefits of digital tickets for fans range from convenience (no printer required, easy to share with friends) to security (more fraud protection). For leagues, it comes down to one thing: data.

• "Rather than knowing the one person out of four who bought the tickets, they now know everyone who uses the tickets," Sports Business Journal's Ben Fischer tells me.
• Knowing who is in a seat, and being able to communicate with them before, during and after the game is hugely valuable. It could also lead to more in-game transactions (i.e. ordering food with your ticket).
• Thanks in part to ticket data, the NFL now has 120 million names in its centralized customer database, Fischer reports (subscription).

Between the lines: Amid this mobile migration, procuring a physical ticket can be challenging. That's a threat to the world of collectible tickets — but collectors have gotten creative, hoping to keep their hobby alive.

• "People are getting tickets by pretending their phones are broken," one collector told The Athletic (subscription).
• A used ticket from Kobe Bryant's final NBA game sold in May for over $40,000 at Goldin Auctions.

Food for thought ... Could digital tickets eventually become NFTs (non-fungible tokens)? What if, as a ticket holder, you got access to exclusive highlights from that game that you could collect or sell?

Well, that was fun. Here's a look back at college football's opening weekend, which began Wednesday and concluded Monday night.

Awards:

• Best performance: Kenneth Walker III, a Wake Forest transfer, ran for 264 yards and four TD in Michigan State's 38-21 win at Northwestern.
• Best moment: 34 months after a freak injury that nearly cost him his leg, QB McKenzie Milton made his long-awaited return and nearly led Florida State past Notre Dame. Incredible story.
• Best color: After LSU coach Ed Orgeron called UCLA's uniform color "Sissy Blue," the Bruins beat the Tigers, 38-27. ... Ole Miss also won Monday night wearing a similar shade of blue.
• Best play: Christopher Smith's 74-yard pick six proved to be the difference in Georgia's 10-3 win over Clemson.
• Best scene: Virginia Tech students wilding out to "Enter Sandman" was electric, but Wisconsin fans "jumping around" takes the cake.

Notes:

• Upsets galore: Six FCS teams beat FBS opponents, headlined by Montana taking down No. 20 Washington. Elsewhere, ETSU beat Vanderbilt, Holy Cross beat UConn, UC Davis beat Tulsa, SDSU beat Colorado State and Eastern Washington beat UNLV.
• Realignment buzz: BYU, Houston, UCF and Cincinnati plan to submit applications this week to join the Big 12, per multiple reports.
• ACC falls flat: For the first time since 1989, two top-10 teams from the same conference lost their openers (No. 3 Clemson and No. 10 UNC).
• Historic streaks: Ohio State has won 22 straight openers (third-longest streak in AP poll era), while Alabama has won 20 straight (fourth-longest).
• 10 TD, one game: Michigan transfer Ren Hefley tossed an FCS record 10 touchdowns in his first start for Presbyterian.

Go deeper: This is what it's supposed to be like (Defector)

Teenagers have taken the 2021 U.S. Open by storm, with three youngsters turning Flushing Meadows into their personal playground and advancing to the quarterfinals.

• Emma Raducanu, 18: Britain's Chinese-Romanian star has lost a combined total of just four games in her last two matches.
• Carlos Alcaraz, 18: The Spaniard, who idolizes Rafael Nadal, is the youngest man to reach the U.S. Open quarterfinals since 1963.
• Leylah Fernandez, 19: The Canadian had quite the weekend, knocking off Naomi Osaka on Friday and turning 19 on Sunday.

Men's QF: Novak Djokovic is three wins away from completing the calendar Grand Slam and winning his record 21st major.

• Today: Botic van de Zandschulp vs. No. 2 Daniil Medvedev, 12pm ET; No. 12 Felix Auger-Aliassime vs. Alcaraz, 8:15pm
• Tomorrow: No. 4 Alexander Zverev vs. Lloyd Harris; No. 1 Djokovic vs. No. 6 Matteo Berrettini

Women's QF: None of the remaining eight women have won a U.S. Open, and just one —Karolína Plíšková (2016) — has played in a final.

• Today: No. 5 Elina Svitolina vs. Fernandez, 2pm; No. 8 Barbora Krejčíková vs. No. 2 Aryna Sabalenka, 7pm
• Tomorrow: Raducanu vs. No. 11 Belinda Bencic; No. 4 Plíšková vs. No. 17 Maria Sakkari

Wild stat ... 43 Americans were in this year's field. None remain.

⛳️ Cantlay crowned: Patrick Cantlay won the Tour Championship on Sunday, a victory worth a cool $15 million. It's been quite the ride for the 29-year-old, who nearly lost his career to a fractured spine.

🏀 "The W25": The WNBA unveiled the top 25 players in league history, a list that includes 10 current players.

🏒 NHL in Olympics: After missing the 2018 Winter Olympics, NHL players will be able to participate in Beijing.

🇯🇵 Suga stepping down: Japan's Prime Minister Yoshihide Suga will step down after one year in office. He saw his approval rating plummet following a COVID-19 surge that coincided with the Tokyo Games.

⚽️ 36 in a row: The Italian men's soccer team has gone 36 straight matches without losing, breaking the record previously held by Brazil (1993-96) and Spain (2007-09).

🏀 BIG3 title game: Jarrett Jack's game-winning triple led Trilogy past 3 Headed Monsters, 50-45, to win the 2021 BIG3 championship.

⚾️ Walk-off slam: Milwaukee's Daniel Vogelbach hit a pinch-hit, walk-off grand slam Sunday, fulfilling every kid's backyard baseball dream.

🎥 Wild video: Dario Costa, a professional race and stunt pilot, just became the first person to fly a plane through not one, but two tunnels.

Mysterious football schools are having a moment. First, it was Bishop Sycamore. Now, it's North American University.

Catch up quick: North American was blown out by Lamar on Saturday in a game broadcast on ESPN+. But the story isn't the game — it's NAU's strange backstory.

• ESPN didn't even have a logo for the Stallions, who played a D-III school the week before. Next week, they play Louisiana Community Christian College, whose address is a strip mall unit.
• NAU appears to operate out of a single building on the side of a desolate highway in Houston. It was accredited by a scandal-ridden organization and falsely claims to be a member of the NAIA.
• NAU has ties to the Gülen movement, a Turkish religious group, and its president is on Turkey's most wanted terrorists list.

The big picture: Turns out, NAU is on the NCAA's list of "non-countable opponents." These institutions don't meet membership requirements, meaning games and statistics against them simply don't count.

• Other schools on the list include American Sports University (San Bernardino, California), Atlantis University (Miami) and University of God's Chosen (Fayetteville, North Carolina).
• Very little information can be found about these schools online, and most of their websites look like they were built on GeoCities.

Meanwhile ... The Bishop Sycamore saga continues, with new coach Tyren Jackson leaning fully into the "fake school" narrative. "We do not offer curriculum," he told NBC4. "We are not a school." Oh.

TOLEDO, Ohio — Europe retained the Solheim Cup (women's version of Ryder Cup) on Monday, clinching just its second victory on U.S. soil.

NASHVILLE — The USMNT settled for a disappointing 1-1 draw against Canada on Sunday, its second straight underwhelming performance in World Cup qualifying. Next up: Honduras on Wednesday.

TOKYO — The Paralympics concluded Sunday, with China atop the medal table, followed by Great Britain and Team USA. Best moments.

ZANDVOORT, Netherlands — Sunday marked the first Dutch Grand Prix since 1985, and Red Bull's Max Verstappen wasted no time winning in front of his home crowd.

The NFL season is fast approaching. While we eagerly await its arrival, we're counting down the league's top 20 players.

• Player: Travis Kelce, TE (Chiefs)
• Age: 31
• College: Cincinnati
• Contract: 4 years, $57.3M (FA in 2026)
• 2020 stats: 15 games; 105 receptions, 1,416 receiving yards, 11 TD
• 2021 fantasy: No. 12 ADP (average draft position)
• Week 1: Chiefs vs. Browns

The big picture: Today's NFL is well-stocked with elite tight ends, none better than Kelce, who's coming off a historic age 31 season.

• By the numbers: Kelce set a Chiefs single-season record with 105 receptions in 2020 and dropped just one pass on 146 targets. His 1,416 receiving yards were the most ever by a tight end.
• Wild stat: Kelce is the only tight end in NFL history with five 1,000-yard seasons, and the only one multiple 100-catch seasons.

What they're saying: "Super savvy, instinctive, big — he's the perfect storm," an AFC scout told ESPN (subscription).

ICYMI: 20. Dalvin Cook; 19. Trent Williams; 18. Bobby Wagner; 17. Tyreek Hill; 16. Jaire Alexander; 15. Stefon Diggs; 14. Myles Garrett; 13. Jalen Ramsey; 12. George Kittle; 11. Josh Allen; 10. Russell Wilson; 9. T.J. Watt; 8. Derrick Henry; 7. Quenton Nelson; 6. Davante Adams

18 years ago today, Andy Roddick won the U.S. Open with a three-set victory over Juan Carlos Ferrero.

Why it matters: Roddick remains the most recent American man to win a Grand Slam. He's also the most recent to claim the world No. 1 ranking, which he held from Nov. 30, 2003 to Feb. 1, 2004.

The Guerreros — Vlad Jr. and Vlad Sr. — are the second father-son duo in MLB history to each post 40-HR seasons.

• Question: Who's the other duo?
• Hint: One batted righty, one batted lefty.

Answer at the bottom.

Source: Giphy

From footballs to baseballs to frisbees, the weekend was full of spectacular catches.

1. ⚾️ Are you kidding?
2. ⚾️ Ben Gamel!!!
3. 🏈 Ronnie got robbed
4. ⚾️ Unreal play in center
5. 🏈 Look ma, one hand
6. ⚾️ Giancarlo!!!
7. ⚾️ Dansby calls game
8. 🏈 You got Mossed!
9. 🥏 Full extension
10. 🏈 How'd he even get there?

Watch all 10.