Robin Berretta, wearing a blue Giants No. 27 Brandon Jacobs jersey, travelled from New York to Landover, Md., for the game at the Washington Redskins. Some of her friends suggested she shouldn't attend.
"Everyone's very paranoid," Berretta said. "And they're not even from New York."
She was unfazed, saying, "I even took the Metro."
In presentations relayed to video screens around the league, "Taps" was played from Shanksville, Pa., where one of the hijacked jets crashed a decade earlier; Arlington National Cemetery in Virginia; and Hoboken, N.J., across the Hudson River from the World Trade Center site. A recorded message from actor Robert DeNiro was broadcast on videoboards reminding fans that "we honour those brave men and women by continuing to show our unity and strength as a country."
NFL Commissioner Roger Goodell marked the day in Landover and East Rutherford, N.J.
"We remember our great country and the people that died in this tragic incident, the first responders and their families and all the people that kept our country safe," he told FOX from the sidelines of the Giants-Redskins game. "This is a chance for everyone to come together and feel great about our country, the sacrifices so many people have had and what we all have in front of us. We've got a lot to be proud of."
Reminders of the changes wrought by that sorrowful day were apparent outside MetLife Stadium in East Rutherford, where every car entering the parking lots for the Cowboys-Jets game was checked by New Jersey State Troopers with bomb-sniffing dogs.
"It shows they're not taking any of this lightly," said Lee Loughridge from Mount Arlington, N.J. "I'm glad they're doing it. This is serious. We knew there would be delays, so we just came early and didn't have to worry."
Jets players wore navy blue T-shirts during warmups with the words "Never Forgotten" on the back.
"Actually, I would've felt uncomfortable if I hadn't seen all the security here today," said Lamar Williams, from Paterson, N.J.
Former U.S. President George W. Bush praised the rescue workers of that day in a televised pre-game show segment prior to the openers, then did coin-toss honours at Cowboys-Jets, the lone night NFL game. Yet another field-long flag was pulled across the turf as hundreds of hands reached out to touch it, including coaches and players. The skirl of bagpipes filled the air with "Amazing Grace," which, at times, was drowned out by fans' cheers of "U-S-A."
At the U.S. Open's women's final at Arthur Ashe Stadium, a "9-11/01" logo was painted next to the blue court, and Queen Latifah and the Jubilation Choir performed a soulful rendition of the anthem. The Marine Corps colour guard unfurled a court-sized flag.
Before losing to Australia's Sam Stosur, Serena Williams tweeted: "My Thoughts and prayers to all who lost loved ones on 9-11. I know the entire country is with you today. I'm playing for you today."
Pre-game ceremonies were followed by moments of silence at Major League Baseball parks. There was a candlelight ceremony under dimmed lights at New York's Citi Field, but MLB denied a request by the Mets to wear caps honouring the NYPD and FDNY.
Mets players briefly considered defying MLB, then acquiesced.
"What are they going to do, fine us?" catcher Josh Thole said.
Joe Torre, MLB's executive vice-president for baseball operations, told The Associated Press the decision was made to keep policy consistent throughout baseball and that "certainly, it's not a lack of respect."
At the Nationals game in Washington, two red, white and blue logos were painted on the field in foul territory along the base lines, with the date "September 11, 2001" and the words: "We shall not forget." The Nationals also wore blue jerseys with a stars-and-stripes background for the team's 'W' logo.
"Frankly, I was a little bit skittish with regard to coming out to a ballpark and large gathering of people with feelings of how scared we were 10 years ago," said Joe Bailey, a 40-year-old fan from Bethesda, Md. "I think as part of our resolve, it's to go ahead and continue on in the American way and do what we do, and one of those things is to be passionate about baseball."
In Anaheim, Calif., Derek Jeter, Jorge Posada and Mariano Rivera of the New York Yankees caught ceremonial first pitches from two first responders and a survivor of the attacks.
"I wish we were at home with the people of New York," Posada said.
The anniversary also was observed at soccer matches in England, Walker Cup golf in Scotland and at the Rugby World Cup in New Zealand.
In Tampa, Fla., the Buccaneers arranged a surprise reunion during the first half two-minute warning for family and close friends of Army Sgt. Scott Osborn, who was returning from active duty in Afghanistan. The Osborn family lives in St. Petersburg.
At sun-splashed Soldier Field in Chicago, fans applauded the national anthem from start to finish — a tradition at NHL Blackhawks games — while tenor Jim Cornelison sang an unusually spirited anthem before the Bears hosted the Atlanta Falcons.
The ceremonies coincided with the regular-season return of the NFL following a summer of labour strife that threatened to stop play for the first time since 1987. The league planned to auction game-used items and donate US$1 million to three memorials and two charities related to the attacks. The balls used for the kickoff of each half were inscribed with special 9-11 logos. Carolina's Steve Smith wore red-white-and-blue gloves and cleats for his team's game at Arizona, catching two touchdown passes in a 28-21 victory.
Jets players wore similar patriotic gear, and Cleveland Browns tight end Benjamin Watson donned red-white-and-blue gloves that read: "Never Forget."
At Kansas City's Arrowhead Stadium, the Chiefs and Buffalo Bills helped 150 firefighters and first-responders to hold up an American flag that stretched from end zone to end zone and sideline to sideline. "American Idol" winner David Cook sang the national anthem, punctuated with a flyover of A-10s from Whitman Air Force Base and crowd chants of "USA! USA!" At halftime, three F-18s streaked across at halftime and names of 9-11 victims were scrolled on the scoreboards.
In Baltimore, fans at the Ravens-Steelers game were given miniature American flags, the band spelled out "U-S-A" and military personnel and first-responders helped move the flag from one sideline to the other.
At Jacksonville, two Jaguars players with military backgrounds carried U.S. flags. Cornerback Will Middleton, whose brother is in the Navy, and fullback Brock Bolen, whose father was awarded three Purple Hearts, led the team out of the tunnel.
"Taps" also was played before the racing program at New York's Belmont Park.
Before the opening kickoffs, Bush appeared in a 90-second opening sequence of "Fox NFL Sunday" titled, "The Journey."
"What is a hero?" Bush asked. "In the midst of great danger ... nobody asks to be a hero. ... We started to heal with the help of our national pastimes, with the flip of the coin and the roar of the crowd."
In England, there was a moment's silence before both Premier League games. Fulham midfielder Clint Dempsey, who is from Texas, and his teammates lined up with arms around each other's shoulders before their match against Blackburn at London's Craven Cottage. Players from both teams wore black armbands on their left sleeves.
In Aberdeen, Scotland, the U.S. captain Jim Holtgrieve read a letter to the team from Bush urging the Walker Cup golfers to "remember those who have defended your liberties and way of life." Bush's great-grandfather, George Herbert Walker, played a key role in the start of the amateur showcase.
In New Zealand, the U.S. Eagles rugby team attended a memorial service at a local church in New Plymouth. Thirty players, wearing grey suits with red-white-and-blue ties, sat alongside the U.S. Ambassador David Huebner. The U.S. Marine Corps Pacific band played. The Eagles later lost their World Cup opener to Ireland, 20-10.
AP Sports Writers Greg Beacham, Rachel Cohen, Chris Duncan, R.B. Fallstrom, Howard Fendrich, Rick Gano, David Ginsburg, Mattias Karen, Mark Long, Janie McCauley, Richard Rosenblatt, Howie Rumberg, Dennis Waszak Jr., Joseph White, Barry Wilner and Tom Withers, Associated Press writer Gordon Brown, and AP freelance writer Daimon Eklund contributed to this report.