Paul O’Donovan provides thrills in races – even semi-finals. As the temperatures rocketed up the 30s here at the World Championships in Rotterdam, the Irishman put in a flying finish to win through to the A Final of the lightweight single sculls.

The Olympic silver medallist and European gold medallist in the lightweight double was sixth at the 500 metres, and still fourth – and out of an A Final place – at 1,000 metres.

Then he did his magic thing, charging up through the places. But Rajko Hrvat of Slovenia, the silver medallist at last year's World Championships, held firm in first. The two raced to the end.

Second would have done for O’Donovan, but he was not prepared to settle for it. He had just .6 of a second to spare, but it was enough to win.

“I didn’t think I got off to a good start. I mean I was last at 500 metres. I kept plugging on at it, getting back at the leader,” O’Donovan said. “The Slovenian generally makes a mad burst in the middle but he was still in it with 150 [metres] to go. I got there anyway.”

O’Donovan’s plans for today are short pieces of training and “to get a bit of sleep”. For Saturday? “To give it a go, to go out and win it.”

His main rival for the gold is the experienced Lukas Babac. The 31-year-old Slovakian won the second semi-final. He is the reigning European champion in this event and, like O’Donovan, has won all three of his races at the World Championships so far.

Ireland will have two chances of senior World Championship medals on Saturday. The Ireland lightweight pair of Mark O’Donovan and Shane O’Driscoll raced hard in their semi-final. They made repeated charges against leaders and eventual winners France, testing their mettle through the race until the very final stages. They finished second.

In their hunt for a medal they may have to oust the French. The hot tip for gold will be reigning world champions Britain, with Coleraine’s Joel Cassells in the bow seat. They won their semi-final, with Denmark second.

Ireland had two under-23 crews in A Finals. The lightweight pair of Shane Mulvaney and David O’Malley finished fourth.

They were towards the back of the field early on, but raced hard in the closing stages to try to break into the medals. Switzerland overtook Greece to win, with Turkey taking bronze.

The under-23 lightweight quadruple were one place farther back in their final. They won a private battle with Sweden to avoid last as the crews closed up at the end of a race which was won by Britain from Germany and Italy.

The Ireland under-23 heavyweight quadruple made a false start in their B Final and finished sixth.