LONDON — McKayla Maroney didn’t need to look at the scoreboard. Neither did Louis Smith.
The Olympic gold medals they were expected to win were going to someone else.
‘‘It happens. It’s gymnastics,’’ Maroney said. ‘‘You can’t be perfect, and sometimes things don’t go as you planned.’’
Maroney wound up with a silver on vault after a rare fall Sunday, while Smith was on the wrong end of tiebreaking rules for a second straight Olympics. Despite finishing with the same score as Krisztian Berki on pommel horse, the Hungarian got the gold and Smith the silver because Berki’s execution mark was a tad better.
Still, Smith was hardly going to complain.
Four years after giving Britain its first Olympic medal in 84 years, he now has three. What’s more, gymnastics has become such a big deal in Britain that the Duchess of Cambridge, formerly known as Kate Middleton, had a front-row seat for the first day of event finals. Teammate Max Whitlock won the bronze on pommel horse, giving the British three medals — the same number they won from 1908 to 2004, before the British renaissance began.
‘‘I could have been standing here without a medal, tears running down my face,’’ Smith said. ‘‘I’ve got a second medal here. I’ve got three Olympic medals. All those years ago, I never thought I’d go to the Olympics, so I’m very happy right now.’’
In the other event final, Zou Kai won his fifth career gold medal, defending his title on floor exercise.
Maroney, the defending world champion on vault, was considered pretty much a lock for the gold medal, which would have given the US women three in the first three gymnastics events. Maroney never makes errors in training or in competition, and no one in the world comes close to her execution. She won her world title last year by almost a half-point and topped qualifying at these Games by a similar margin.
‘‘I wasn’t focused on getting a gold medal,’’ the 16-year-old said. ‘‘I just wanted to prove to everybody that I could hit two vaults and I could try to do my best for USA.’’
Her first vault was the difficult Amanar — a roundoff onto the takeoff board, back handspring onto the table, and 2½ twisting somersaults before landing. She got such great height off the table the fans in the first few rows had to look up to see her. Her form was perfect in the air — legs pencil-straight, body tightly coiled.
She took a hop on her landing, and came down out of bounds. But even with that 0.3 deduction, Maroney still scored 15.866, including a whopping 9.666 for execution.
Another vault like that, and the gold was hers. But she appeared to land the second one on the back of her heels, and her feet slid out from under her. Maroney fell to the mat with a loud ‘‘plop!’’ drawing a gasp from the crowd.
She scored just a 14.3, giving her an average of 15.083. Coach Arthur Akopyan tried to console her, but Maroney looked shell-shocked as Sandra Izbasa of Romania did two impressive vaults to claim the gold. It was Izbasa’s second Olympic gold, following her title on floor exercise in Beijing.
‘‘I already knew that I pretty much only had the silver medal,’’ Maroney said. ‘‘I really didn’t deserve to win a gold medal if I fall on my butt.’’
Smith made no such mistake, but the outcome was the same. And eerily similar to four years ago, when he dropped to bronze on a tiebreak.
‘‘I knew straight away that it was going to come up in second place. I knew it,’’ Smith said.
Sure enough, despite scoring identical 16.066s, Berki won the gold because his execution mark was higher — by 0.10 points.
‘‘You know, I did fantastic,’’ Smith said. ‘‘To be beat by Krisztian, he’s one of the best pommel performers in the world, and to come in second to him at an Olympic Games, that’s a good feeling.’’