Andrew Selby failed to guarantee Britain's fifth boxing medal as he lost to Robeisy Ramirez Carrazana.
But Evans good for a medal after sneaking past Canadian Clayton
Andrew Selby suffered a shock defeat to Robeisy Ramirez Carrazana, meaning the British flyweight misses out on a medal at London 2012.
The 23-year-old Welshman was one of the favourites, particularly as he had gone into the tournament ranked as the No.1 in the world.
Yet despite also having claimed a silver at last year's world championships, he was beaten 16-11 by his classy Cuban opponent.
There was a ferocious pace to the contest right from the outset, with Selby opening up with a whirlwind combination that forced his rival to cover up.
However, despite being the one on the back foot for long periods, Carrazana found himself 5-4 ahead at the end of the first after landing the cleaner shots.
In the second the South American moved further clear, opening up a five-point gap after Selby too often found himself flat-footed and backed up against the ropes.
Left with a mountain to climb in the last the reigning European champion came out all guns blazing, only to be picked off on the counter in a round that was eventually scored at four apiece.
Ireland will definitely win a medal in the flyweight division after Michael Conland beat Frenchman Nordine Oubaali 22-18 in his quarter-final.
Good Evans
There was better news later on for Selby's compatriot Fred Evans, as he sneaked past Canadian Custio Clayton to make sure of a fifth medal for Great Britain in the ring.
The welterweight led 7-2 after the first round but Clayton came on strong to earn a 14-14 draw, meaning the outcome was decided on countback.
It was Evans who had his arm raised in the end, though he must have breathed a huge sigh of relief after coming close to letting a commanding lead slip away.
He had made a confident start, too, catching Clayton with his southpaw jab and straight left, while he knocked his opponent off balance by a body shot early in the second.
