France coach Bernard Laporte blasted his side's defence after they leaked five tries in their 39-31 victory over the United States on Saturday.
The 2004 RBS 6 Nations champions, playing their first international match since March, struggled to overcome their opponents in the first match of their two-game tour of North America.
Trailing 21-17 at the break, Laporte's men fought back in the second half with two tries from Mathieu Barrau and one from Thomas Lievremont.
But the French boss said: "Out of the five tries that we conceded, I believe three of them should not have happened.
"We were not good enough in the positioning and I don't know why. Maybe because of a lack of physical freshness."
Les Bleus captain Fabien Pelous added: "We were really lucky. We experienced difficulties in defence."
France face Canada in Toronto on Saturday and French full-back Clement Poitrenaud warned: "We will need to be more determined and concentrated.
"Defence is capital and we should make sure we don't step back this time."