The French led Wales 16-0 at halftime in the Six Nations earlier this year only to lose 24-19, while last November South Africa overhauled a 23-9 deficit to beat them 29-26 with a last-minute Bongi Mbonambi try at Stade de France.

It looked like deja vu at Tokyo Stadium when, after building a 20-3 lead at the break on the back of some brilliant attacking rugby, the French trailed 21-20 with 11 minutes to go.

This time, though, replacement flyhalf Camille Lopez eased their nerves with a coolly taken drop goal which ultimately secured a 23-21 victory to send France top of Pool C.

"Not so long ago, we would have lost this match. But we kept our heads to win this opening game and make a good start to the tournament," Slimani said.

"It reminded me of a lot of matches. I thought about the game against South Africa at Stade de France, when we lost in the last seconds.

"For the first time in a while, today it went in our favour. It's not over, but, hey, at last it's turning in our favour."

While most of the plaudits for France's purple patch in the first half against Los Pumas went to the backs, Slimani and his fellow forwards also played their part, particularly just before halftime.

With Argentina camped on the France line for a long period they elected to take a scrum penalty.

The French scrum stood up the challenge, however, and secured a penalty that allowed them to break the siege.

The three-times World Cup finalists next face the United States in Fukuoka on October 2 followed four days later by what will be another physical contest against Tonga in Kumamoto.

Their final pool match will be on October 12 in Yokohama against arch rivals England, a contest which is now likely to decide which team tops their section of the draw.

"We cannot allow ourselves to relax ... we must win the next two games," fullback Max Medard said.

"England is an ogre for us. They are several levels above us."

Australian Associated Press