Dupont played 12 minutes of the opening 12-12 Pool C draw against the US, the Americans scoring the equalising try after he had been subbed off.
Dupont again started the second match and crossed for a memorable five-pointer in the hard-fought 19-12 victory over Uruguay, who lost their opener 40-12 to Fiji.
The result meant that France, who play the Fijians in their final pool game on Thursday, were mathematically qualified for the knock-out round later the same day -- at worst as one of the best two teams finishing third in the pools.
"It was a huge atmosphere for us," said Dupont. "It's not common for us to play in this kind of stadium.
"We didn't put ourselves in a good place once again (against Uruguay). We struggled to impose our gameplan, to keep the ball.
"And if you only defend, you logically concede points," he added, lamenting a catalogue of technical and tactical mistakes."
Dupont acknowledged that the "essential thing is the win and that's what we'll take away from that".
"I hope that we'll have taken what there was to take from the stadium, the atmosphere, the surrounds so as to not be too troubled Thursday.
"If we don't raise our level, we won't go very far. We know that and we're capable of doing much better."
Dupont has established himself as one of world rugby's best players and the scrum-half cuts an iconic figure in France.
The 27-year-old took the gamble of missing the Six Nations to make the French Olympic team, a move that led to some criticism.
Dupont factor
But the combative half-back put that to one side, going on to help France to two wins on the World Rugby Sevens Series, including victory in the Madrid finals.
In between, he skippered his club Toulouse to Top 14 and Champions Cup glory in the 15-a-side code.
Against the Americans at the Stade de France, Dupont was named in the starting seven, coach Jerome Daret having previously used the playmaker largely as a super-sub from the bench.
Wearing the number 11 shirt, Dupont's passing ability and counter-rucking were to the fore in a tight opening seven minutes.
A trademark Dupont hand-off and deft offload helped Rayan Rebbadj in for a try, before he produced a great flying tackle to bring down Kevon Williams, forcing a knock-on.
With that, the Frenchman exited the pitch, with two minutes remaining.
The US, however, immediately hit back through Marcus Tupuola to leave the scores level at 12 points apiece.
The crowd gave a collective sigh of relief as Madison Hughes missed what would have been a match-winning conversion.
The second pool match against Uruguay was also close.
But it was another Antoine -- Zeghdar -- who starred for France, the powerhouse a permanent menace and also scoring a great individual try.
But Uruguay stayed in the hunt through Igancio Facciolo.
Then the moment came that the whole stadium had been waiting for. Dupont cleared up an Uruguyan grubber and played namesake Zeghdar into space.
As he hit the ground, his offload found Dupont in support and the Toulouse player twice handed off Mateo Vinals to muscle his way over the line.
"I tried to go right through with it, the tryline was very far away," said Dupont. "Some times it works, other times not."
He was subbed off shortly after, Juan Gonzalez capitalising on an error from the kick-off to drag Uruguay back into the game.
But Joseph grabbed France's third try to secure qualification.
Dupont's presence ensured a 69,000-capacity crowd at the Stade de France, with World Rugby expecting more than half a million fans to attend the six days of sevens action.
The last time Dupont had played at the stadium north of Paris was in a 29-28 defeat for France against South Africa in the Rugby World Cup quarter-final in October.
Dupont's absence from the Six Nations to focus on making the Olympic team did not sit well with many traditionalists.
But his appearance at the Paris Games remains a huge coup not only for French rugby as a whole, but also the organisers.
