Speaking ahead of France's quarter-final against Spain in Donetsk on Saturday, Blanc was not impressed with the mood among his players the day before they lost 2-0 in their final Group D clash in Kiev, a "horrible evening" in the ex-defender's words.
"We felt there was a bit of slacking off in training. Today, having taken stock, the reaction is generally good. This was not the case two days ago," Blanc told reporters.
"Yesterday was a horrible evening. For the players, for the staff, for the people who watched us. We didn't do enough to win.
"We wanted to win the match for two reasons, to qualify and to finish first in our group. We achieved the first objective but not the second."
England topped the group and now face Italy.
Far from fearing France's next opponents, world and European champions Spain, Blanc preferred to speak of his admiration for Vicente del Bosque's free-flowing keep-ball specialists and had some words of advice for his troops.
"We have to mentally accept to run, to run a lot, to run enormous amounts to fill the holes. And when we regain the ball, we'll need speed and depth. That's the equation," he said.
Key to French hopes could be lively winger Franck Ribery, who limped out of training early on Wednesday with a burst blister but a team spokesman said he should be fit.
Blanc will undoubtedly mull changes to his starting 11 after such a woeful display against already eliminated Sweden but one new face is certain, centre-back Laurent Koscielny will replace the suspended Philippe Mexes.
"Many players dream of playing their first match in the European Championship against the title holders. We have nothing to lose and it could be an unforgettable match," an unfazed Koscielny told reporters.
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