Reigning world champion Jordyn Wieber performs on the floor at the U.S. Olympic gymnastics trials in San Jose. She leads Gabby Douglas and Aly Raisman after the first day of competition. (Mike Blake/Reuters)

Jordyn Wieber looks ready for London. As for the rest of the U.S. women, they still have some work to do.

The reigning world champion was about the only one not affected by nerves Friday, breezing through the first night of the Olympic trials and all but assuring herself of the lone guaranteed spot on the five-woman London team. Wieber finished with 61.7 points, 0.3 points ahead of Gabby Douglas, who had to work out of a hole after making a big error on uneven bars, her first event.

Only the winner of the two-day trials competition is guaranteed a spot on the five-woman London team, with the remaining four to be picked by a selection committee following Sunday night’s competition.

“Pretty bad,” Wieber said about wanting that top spot. “I try not to think about the standings, but at the same time, everyone wants that guaranteed spot.”

Heck, some will be happy with a spot after their sloppy performances Friday night.

Aly Raisman, normally rock steady, finished a distant third after a big wobble on balance beam and going out of bounds on floor exercise, where she is the reigning world bronze medalist. Kyla Ross landed her vault on her backside and was fifth. McKayla Maroney fell off both uneven bars and balance beam and was seventh. And reigning Olympic champion Nastia Liukin had another rough night.

Liukin knows she needs to put up huge scores on uneven bars to have any shot at the team, and she failed to do it again Friday night. Clearly out of gas near the end of her routine, she stalled on a handstand on the upper bar and, as the crowd groaned, her legs folded over. She managed to stay on, but it cost whatever momentum she had left. She didn’t get anywhere near the height she needed for her dismount, plopping onto the mat on her backside.

She scored a 14.05, better than she did at nationals three weeks ago, but nowhere close to the 16 national team coordinator Martha Karolyi wants to see.

“Of course any athlete will tell you when they don’t have a great performance, especially when it’s at Olympic trials, it’s disappointing,” Liukin said. “But at the same time you have to come back out there and (show) that you are a fighter and you’re not just going to give up.”

Wieber, the favorite for the all-around title in London, started piling up the points from the minute she took the floor. Wieber does one of the hardest vaults in the world — a roundoff onto the takeoff board, back handspring onto the vault and then 2.5 twists before landing — yet makes it look as easy as a simple cartwheel. She did land with her knees a bit locked, but it didn’t cost her much.

If Wieber has a “weakness,” it’s on uneven bars. She had some struggles at last year’s world championships and again at American Cup, but there were no signs of them Friday night. She was so smooth and controlled she appeared to float as she moved between the bars, and there was a breezy confidence to her release move. She landed her upgraded dismount with such ease it was as if she’d been doing it for years, the only movement coming from coach John Geddert, who hopped across the floor pumping his fists in celebration.

While balance beam tripped up Raisman and Ross, Wieber may as well have been in a parking lot for as easily as she made her tricks look on the 4-inch wide slab that’s 4 feet off the ground. She landed one of her aerial skills on one foot, slowly sweeping the other along the side of the beam. Just watching her twisting back somersault is enough to make you dizzy, but she landed it perfectly and moved right onto her next trick.

She ended her night with a rousing floor routine that may as well have been a victory lap. Floor is the one event the stoic Wieber lets her personality show, and she was even sassier than normal as she strutted and pranced through her dance moves. She stuck the landings of her tumbling runs so emphatically you could hear it throughout the arena, and when she finished with her hands thrust in the air, the arena erupted.

“I just loved the way she went out and attacked it,” Geddert said. “She had some issues so there’s room for improvement and it’s my job to point that out. I don’t think we’ve ever had a meet where I didn’t say, ‘There are things to improve.’ We’re still waiting for the perfect meet.”

Douglas has emerged as Wieber’s biggest rival, reminiscent of the battle between Liukin and Shawn Johnson four years ago. But she couldn’t overcome a mistake on her very first event.

Going up last on uneven bars, she had the crowd oohing and aahing with what’s become her trademark: a release move so massive the folks in the first few rows had to crane their necks to see her as she launched herself up and back over the bar, her legs piked so perfectly she could have touched her knees with her nose. But Douglas lost her rhythm midway through the routine and stalled on a pirouette. She stayed motionless for several seconds, gripping the bar tightly with her hands and using every bit of muscle she had not to fall off.

“Man, I was using every single muscle,” Douglas said. “I just pulled it out of nowhere. That was God. And someone blowing (on) me from the stands.”

She hung on somehow and completed the rest of her routine, but her 15.250 was well below her usual score.

Douglas also had a big wobble on balance beam. But she rebounded with the second-highest score of the night on floor exercise.

Turn on Douglas’ bouncy techno music and it’s like turning on a light. Make that a spotlight that could power a small city, actually. Unlike many gymnasts, whose could use Muzak for as much as they acknowledge their music, Douglas glands her tumbling runs right on the biggest beats, giving them both extra oomph. And the air she gets on uneven bars? She’s got some pretty mean hops on floor, too, looking like a rubber ball as she bounced from one landing into her next skill.

“I couldn’t let it get to me,” Douglas said about the mistakes. “I do want (the top spot) very badly, but I’m trying not to think about being first.”

— Associated Press