David Davies has conceded his hopes of competing in the open water event at the Olympic Games are all but over.
Davies needed a top 10 finish or to beat rival Daniel Fogg at the FINA Olympic Marathon Swim qualifier to all but secure selection.
finished 38th in Portugal while Fogg's 35th place
means he is in pole position to be named in the squad.
"I believe it's all over really," said 27-year-old Davies, the 2008 Olympic open water silver medallist.
Davies and Fogg must now wait as the British Development and Open Water Coach and the National Performance Director meet to decide who they will nominate to the British Olympic Association before the squad is named on 20 July.
Davies had already confirmed an Olympic spot in the 1500m and believes Fogg, England's 1500m Commonwealth Games bronze medallist in Delhi two years ago, deserves the nod.
PROFILE OF DAVID DAVIES
Born: 3 March, 1985 in Barry
Olympic silver medallist - 10km (2008)
Olympic bronze medallist - 1500m freestyle (2004)
Commonwealth Games gold medal - 1500m freestyle (2006)
Commonwealth Games bronze medal - 400m freestyle (2006)
British record holder 1500m - 14:45.95
"The rules state that Britain gets one spot being a home nation if no Brit has gained qualification through the normal process," Davies told BBC Wales Sport.
"It's open to the selectors but I assume and I think they should go with Dan, who beat me.
"He swam at the World Championship last year, he was Britain's top swimmer last year and I think that's the way the selectors will go."
Davies won 1500m bronze in his debut Olympics at Athens 2004 in the pool and came within a whisker of winning gold at the Beijing Olympics.
On Sunday in Portugal, Fogg finished in one hour 49 minutes and 38 seconds - 34 seconds ahead of Davies.
Both were in the main pack for the first of six laps but by the second, the lead group broke away, leaving Fogg and Davies fighting for the top British spot.
Turning to start his final lap, Fogg pulled away from Davies taking a 17-second lead and held on down the stretch.
"I'm obviously disappointed," added Davies. "It wasn't the result that I wanted to try and qualify for the Olympics. I knew it was going to be a tough one. Unfortunately I've come up a bit short.
"As far as I'm concerned all I've got to do is dust myself off and recover from this event. Either way I've still got to prepare for the Olympics in eight weeks' time.
"At the moment, unless I'm told otherwise, I'll just be swimming in the 1500m now."