A sudden downpour sent the players scurrying off the pitch after five minutes at Donbass Arena, but play resumed following a 58-minute delay and France went on to secure a 2-0 win that sent them top of Group D.
Having seen his side produce a timid showing in the opening half hour of their 1-1 draw with England on Monday, Blanc said the deluge in Donetsk threatened to upset his players' focus at a crucial moment. "Our fear was that we wouldn't be able to play the game, because we really wanted to play," he said.
"We were 30 minutes late for the EURO against England and the weather meant that we still couldn't start properly against Ukraine. But things were sorted out. The stadium was still in a good state and the pitch enabled us to play.
"We were worried the conditions would make it difficult. We planned certain things in case the pitch didn't let us play, changes of strategy, but we quickly saw the pitch was in good condition and we were able to play our football."
Franck Ribery, the official man of the match, said Blanc had helped keep his players focused during the long wait in the bowels of the Shakhtar Donetsk stadium. "He stayed very close to us," said the Bayern Munich winger. "It's never easy, situations like that. Honestly, we thought we weren't going to be able to play.
"But we're professionals. It took us about 15 minutes to warm up and then we went back out, pressed Ukraine high up the pitch, and got the win we wanted."
Blanc made two changes to his starting line-up, bringing in Gael Clichy at left-back and replacing Florent Malouda with Jeremy Menez, who lined up on the right wing and claimed the opening goal in the 53rd minute.
Blanc said the objective was to capitalise on Ukraine's habit of leaving their flanks exposed, and he paid special tribute to Paris Saint-Germain winger Menez. "We tried to play high up the pitch and be aggressive, and we tried to play on the flanks because we'd noticed that when Ukraine lost the ball, they tended to regroup in the centre of the pitch," he explained.
"[Menez] is someone who needs confidence, but he has an increasingly rare quality, which is the ability to play behind the opposition defence. We knew Ukraine would leave space. They try to play football - it's the philosophy of their coach [Oleg Blokhin], but they leave lots of space.
"Jeremy is a quick player and he was able to exploit it. He still needs international experience, but tonight was very encouraging for him."
Yohan Cabaye gave France a two-goal cushion they would not relinquish three minutes after Menez had broken the deadlock and Blanc was left to savour a first French victory at a major tournament since the 2006 FIFA World Cup™ in Germany.
"We're very happy to have won," he said. "Six years of official competitions without a win is a long time. I hope the next one won't take six years because if it does, I won't be here to talk about it because I will have been sacked well before then!"