Thiago Silva felt fatigue for Paris Saint-Germain's international stars came into play as they ground out a 2-0 Ligue 1 win over Nantes on Saturday.
Angel Di Maria put Unai Emery's side ahead in the 13th minute but the champions had to wait until Jese Rodriguez's late penalty to make the points safe.
PSG are now unbeaten in nine games across all competitions but former Sevilla boss Emery continues to come in for criticism, with former player Vincent Guerin adding himself to the dissenting voices this weekend.
Nevertheless, Silva believes the value of three more points in their title defence outweighed any sense of disillusion over PSG's display against Nantes.
"It was complicated, like all games," he told reporters.
"We have a lot of internationals so there was a lot of fatigue after those selected returned.
"It is always difficult but the most important thing is to have taken the three points. We play to win and the mission is fulfilled."
Emery's men take on Arsenal next, with both sides gunning for top spot in Champions League Group A having secured qualification for the knockout stages during the previous matchweek.
"I hope that we will be better on Wednesday against Arsenal," Silva added. "We want to finish first and to do this we must win there."