LONDON (AP) ― Park Tae-hwan wiped away tears at the end of his long day. A day that nearly ended prematurely and instead concluded with a bittersweet silver medal.

After getting reinstated from a temporary disqualification following morning heats, the South Korean had his Olympic 400-meter freestyle title taken away by Chinese rival Sun Yang.

Park led throughout the first half of the race Saturday and was under world record pace for a long stretch, but Sun pulled ahead in the final 150 meters.

“I swam really well, it was a little bit of a pity that I came second,” Park said through a translator, wiping away tears as he spoke. “There was a lot going on for me this morning but I swam as well as I can, I have no regrets about this morning.”

Sun won in an Olympic record 3 minutes, 40.14 seconds while Park touched in 3:42.06. Peter Vanderkaay of the United States took bronze in 3:44.69.

Park became the first South Korean swimmer to win an Olympic title four years ago in Beijing, and it was a stunning development when he was disqualified for a false start after leading his heat.

South Korea filed a protest, which was rejected, then an appeal to FINA’s jury of appeal, which eventually ruled in Park’s favor.

The sport’s governing body FINA made the decision several hours after the heat, following a video review.

“It has been a long day for me,” said Park, who trains under Australian coach Michael Bohl. “It was very difficult for me in that period between heats and finals. ... I’ve been waiting for this day and there was a lot going on in this day.”

Park’s heat time was 3:46.68 seconds, which qualified him in fourth position. The reversal of the disqualification knocked out Ryan Cochrane of Canada, who had taken the final qualifying position in eighth.

The jury’s decisions are final, meaning Canada couldn’t appeal.

“I was surprised, because I left the pool thinking he was in,” said Randy Bennett, the head coach of the Canadian team and Cochrane’s personal coach. “He took it well and he’s already started to get ready for the 1,500, his best event.

“He did what I told him to do and won his heat, but he probably needed to be a little faster,” Bennett added. “You need a little luck in these situations and we were just on the short end of the stick.”

Park was first to touch the wall in his heat and appeared bewildered when told of the disqualification.

FINA executive director Cornel Marculescu could not explain why the judge on the pool deck called for a disqualification.

“It’s a very good question,” Marculescu said. “Human error maybe.”

The judge involved, Bill Hogan, was Canadian, but Swimming Canada chief executive Pierre Lafontaine rejected any speculation that national interests triggered the false start call.

“You pick these officials and some are from different countries. Can you imagine the process if you have to start removing the official when there is a heat of a different competitor?” Lafontaine said. “These people are taken because of their quality in what they do, and I’m confident in FINA.”

The pool lanes inside the Aquatic Centre are numbered in reverse order from most pools to please a request from TV broadcasters, and there was also speculation that the order may have confused the judge ― or even that someone else should have been disqualified instead of Park.

“I don’t believe so,” Lafontaine said. “It’s pretty similar. Everything is pretty clear.”

Park’s next event comes Sunday morning with the 200 free heats.

“That’s my concern now,” he said. “My coach told me we have to forget about today and focus on the 200 tomorrow. It’s not going to be easy, though. This doesn’t happen to me every day.”