RADCLIFFE swimmer James Guy is into the Olympic semi-finals of the 100m butterfly after putting in the eighth fastest time in the first-round heats.

The 20-year-old made a successful return to the pool a day after claiming silver in the 4x200m freestyle relay.

He won heat three in 51.78secs, with Singapore's Joseph Schooling fastest qualifier in 51.41.

Guy is not expected to challenge for an individual medal in the event, but is taking part as a warm-up ahead of swimming the butterfly leg of the men's 4x100m medley – the final event of the Olympics in the pool.

"That was a very impressive swim from James Guy," said BBC commentator Adrian Moorhouse.

"It is good for the individual but also for those of us hoping for a great relay in the last event of the whole Olympics in the pool.

"It is really positive to see James Guy do that."

Guy, who is a freestyle specialist, having finished sixth in the 400m and fourth in the 200m freestyle, as well as winning silver in the relay, has stepped up to fill the team's weakest discipline in the 100m medley relay.

He will continue his preparations for what could be a second medley medal when he takes part in the 100m butterfly semi-finals in the early hours of Friday morning, from 3.34am British time, with a place in the final now a realistic objective.