When Craig Bellamy scored the first goal for the British men’s soccer team Thursday night, the stands at Old Trafford looked as patriotic and engaged as one might expect. Union Jacks waved in the crowd of 72,176, which largely stood. Bellamy slid into the corner, absorbed his teammates as they fell on him, and everyone celebrated an early lead over Senegal.

Yet this night at this place, the opening of the Olympic men’s soccer tournament even before the Olympics officially open themselves, felt a tad off.

“It was a bit strange,” said Ryan Giggs, Britain’s 38-year-old captain and a regular with Manchester United.

That might duly capture all of Britain’s feelings about this 16-team event. The Olympics are supposed to be the pinnacle of sport, and for almost all of the 36 that will be contested here, that’s the case. A glaring exception: Men’s soccer. Most of the best players in the world aren’t here for this event, so some of the best fans in the world are happy to show up and take in a match, but also happy their moods and their thoughts and their lives over the coming weeks won’t be colored by the result.

“We haven’t got high expectations,” said Ben Moghan, who draped himself in one of those Union Jacks. “There’s no pressure. It’s not as important.”

How, in a soccer-mad country now hosting the world’s premier sporting event, can this be? For starters, Team GB, as it is dubbed, is more than a bit of an anomaly. The group is a hodgepodge of players from England, Scotland, Northern Ireland and Wales — each of which would field its own team when trying to qualify for, say, a World Cup.

The event, then, is more important for players such as Giggs and Bellamy, both Welshmen whose national side hasn’t advanced to the game’s greatest stages, than for some of the English players. Indeed, Bellamy called the opportunity to be an Olympian “an honor.”

That, too, is how the match sold out, and the fans filled up.

“We wanted to be part of the Olympics,” said Adrian Boyd, who traveled from his home in Castle Donington, 80 miles away, with his wife, their two sons and a young friend, another couple and their son. “All these kids, they all play football. We’re all football fans. We just thought, ‘Where could we go?’ ”

The venue, too, was a draw. None of the children had been to Old Trafford, home to Manchestesr United, which still dubs its home pitch the “Theatre of Dreams,” the name given to it by Bobby Charlton, the club’s star in the 1950s and ’60s. Charlton is honored just outside the stadium with a statue. In the rendering, he is joined by fellow legends George Best and Denis Law atop an inscription: “The United Trinity.” They face a similar statue, which sits above the East stands, of Sir Matt Busby, the manager who led United to the 1968 European Cup title.

It was Busby, in fact, who coached the British entry in the 1948 London Games, a squad that reached the semifinals.

But in the subsequent six decades, there is not much Olympic football history. Its last Olympic appearance: 1960. On this night, Old Trafford had the history. The home team didn’t.

“I don’t think people care too much,” said Tim Moghan, 27, who joined his brother Ben in wearing a flag. “They want to see some good games, and have some fun.”

“The players just aren’t up to the standard,” said older brother Daniel, who eschewed the flag.

There, then, is perhaps the most significant reason why the Olympic tournament is met with a shrug-the-shoulders-and-pass-the-chips attitude here. Olympic men’s soccer teams, unlike their women’s counterparts, are limited to players 23 and under, with three exceptions per squad.

All of that contributed to the odd feel of this match against Senegal. There were several attempts to start the wave, most of them failures. There was some chanting of “G-B! G-B!” And when Senegal scored in the 82nd minute to force a 1-1 draw, there were groans. But for everyone involved, a Premier League game this was not.

“I thought the first 10 minutes, it was a little bit different,” said midfielder Tom Cleverley, who plays for Manchester United. “I’m used to the Stretford End [the famous West end of Old Trafford] roaring, and the fans being right behind us for a United game. But as the game went on, the crowd were fantastic.”

All of this means there is some angst around what, exactly, the tournament means in the host nation of the Olympics. Witness, The Daily Telegraph: “It seems evident on the register of public anticipation, the impending kick-off of the football tournament is hovering between bemused indifference and wholesale apathy.” The paper then called Team GB a “nebulous outfit” playing in a “competition thought of as a pointless add-on.”

The Daily Mail, too, asked the central question: “How many people will actually care?”

The main news Thursday might was the status of 23-year-old Welshman Gareth Bale, a man used to promote Team GB when its uniforms were unveiled last year. Bale pulled out of the Olympics with an injury. He then turned up in Los Angeles, where on Tuesday night he played for his Premier League club, Tottenham Hotspur, in a friendly against the Los Angeles Galaxy and scored a goal.

The easy angle, from London: The Olympics were meaningless enough to be spurned in favor of a preseason friendly.

After the opening goal at Old Trafford, the crowd’s greatest uprising came when Senegal’s Saliou Ciss collided with Bellamy, and no penalty was called. They booed Ciss each time he touched the ball thereafter. But when the final seconds of extra time ticked away, the crowd gathered its flags and its jerseys, and filed out into the night, orderly all the way.

“We’re in it to, obviously, go all the way,” Giggs said. But if they don’t, the sense after the opening match is that even the heartiest soccer fans in a hearty soccer nation will move on, and quite easily.

Other games: Japan stunned gold-medal favorite and 10-man Spain, 1-0. Striker Yuki Otsu scored the winning goal in the 34th minute. . . .

Top-seeded and Group B favorite Mexico did not score any goals and wound up with a 0-0 draw against South Korea. . . .

Honduras squandered a great opportunity to pick up three points when it gave up a goal to Morocco in the 67th minute of a 2-2 draw. . . .

Brazil scored three times in the first half, then held on for a 3-2 victory over Egypt. . . .

Dmitry Baga of Belarus scored on the stroke of halftime for a 1-0 victory over New Zealand. . . .

Admir Mehmedi scored in the fifth minute for Switzerland, but Pierre Aubameyang equalized for Gabon in a 1-1 draw.