Hosts France needed Louis Bielle-Biarrey's late try to make sure of Thursday's 27-12 victory over Uruguay in Pool A of the Rugby World Cup.
A much-changed side were made to work hard for their second win in the tournament by a spirited Los Teros before 20-year-old Bielle-Biarrey, who became Les Bleus' youngest player at a World Cup,crossed with eight minutes left in Lille.
"There's a lot of frustration," France lock Cameron Woki said.
"We would have liked to put in a better performance.
"I think we were a bit relaxed with the opponents in mind. We have to switch that," he added.
No. 8 Anthony Jelonch led Les Bleus, less than seven months after suffering a serious knee injury with head coach Fabien Galthie naming a second-string side to face the outfit ranked 17th in the world.
Centre Andres Vilaseca captained Uruguay, following his brother Santiago in 2015, as they became the first pair of brothers to skipper a country at a World Cup.
After improved renditions of both national anthems compared to those in Friday's opening match, Les Bleus led 3-0 thanks to Melvyn Jaminet's third-minute penalty.
However, the near 49,000-crowd were stunned into silence almost immediately after as Uruguay winger Nicolas Freitas caught Felipe Etcheverry's cross-kick to score in Uruguay's first appearance of this tournament.
The fervent atmosphere was rewarded as Antoine Hastoy crossed from a set-piece move.
Jaminet's conversion and penalty restored a France lead with the hosts 13-5 up after 15 minutes.
Fly-half Hastoy's try was unable to set the tone for a convincing Les Bleus victory with French President Emmanuel Macron, seen drinking a beer during the game, watching on alongside Uruguayan counterpart Luis Lacalle Pou.
Before the half-hour mark lock Romain Taofifenua was sent to the sin bin on his 33rd birthday for a high tackle on Uruguay's Santiago Arata, which was not upgraded by the bunker.
The decision continued the trend of inconsistent calls on dangerous challenges from officials during the tournament.
With half an hour to play, France were denied by the TMO themselves as Gabin Villiere's effort was chalked off before Galthie changed five forwards, including skipper Jelonch.
Bastien Chalureau was of the new faces, making his first appearance after being at the centre of a controversy surrounding his 2020 conviction for racial assault, which he is appealing.
The changes failed to help the home nerves and things worsened as Uruguay full-back Baltazar Amaya crossed and Etcheverry's conversion made it 13-12 with 26 minutes to play.
Los Teros' aspirations of a shock result were short lived, however, as substitute hooker Peato Mauvaka restored France's breathing space, crossing after Etcheverry's attempted clearance was blocked by his own team-mate Carlos Deus.
With eight minutes left Galthie's changes finally had their desired impact, as they did in last week's All Blacks win, with carries inside the Uruguay 22m before Bielle-Biarrey dived over in the corner.
Jaminet slotted the extras before the TMO denied Sekou Macalou what would have been a bonus-point try with three minutes to play.
Los Teros attempted to shorten the score late on before a mix of whistles and cheers welcomed the final whistle.
