Great Britain endured an indifferent day at the Olympic boxing test event on Thursday.
Charlie Edwards and Simon Vallily both suffered defeat in the evening session at the ExCel after what had been a successful start to the day.
Light welterweight Josh Taylor and welterweight Freddie Evans progressed to the semi-final stages in their respective classes in the earlier session.
However, things started to go awry when Callum Smith slumped to defeat in his middleweight bout with Maxim Koptyakov 4-2.
Edwards and Vallily losses followed and Liverpool-born Smith knows he could have done better.
"I am not too disappointed, I know I could beat him," Smith said.
"He was quite clever, circling and then pushing in quick. I'll learn from it.
"I was expected to win but it just wasn't my day.
"It wasn't a very high-scoring fight but I didn't perform to my best."
Defeat comes as a big blow to Smith, whose qualification for London 2012 is yet to be confirmed.
By contract, Evans' performances at the World Amateur Boxing Championships earlier this year has seen his place secured and he continued to impress against Uzbekistan's Jaloliddin Uktamov today.
Having seen fellow Brit Taylor win the first bout 9-7 against American welterweight Jamel Herring, the Welsh fighter secured a semi-final berth with a convincing 16-6 victory.
"It was good to get back out there after the world championships," Evans said.
"It was nice for my family to be able to come and watch as well so it was enjoyable.
"After the first round I knew he was going to come at me so I had to deal with a rush for a minute or so.
"Then in the last round he had to come at me due to being four points behind and I countered that."
Evans and team-mate Taylor will fight again tomorrow, with China's Qiong Maimaitituersun and Jeff Horn of Australia the opponents.
Vallily came close to joining his fellow Britons in the next stage after an enthralling heavyweight contest with Joseph Williams of the United States this evening.
The day's final - and most combative - bout finished level after both the first and second rounds, before Williams saw out the final round 7-3.
Light flyweight Edwards also suffered defeat in his bout with Uzbekistan's Shakhobidin Zoirov.
Despite a strong start and good combinations, Edwards lost 15-11 after three close rounds yet he remained upbeat.
"I can move on from this. It is good experience," he said.
"I will learn from that performances, learn from my mistakes and go on from there.
"I just need to make sure I train that little bit harder because I will always come back for more.
"It is not an Olympic qualifier [so that is a positive]. That is in March so I will need to make sure I go and do it there.
