Paris Saint-Germain head coach Christophe Galtier said his players held a "feeling of frustration" after they were held to a 1-1 draw by Benfica in the Champions League.
Lionel Messi became the first player to score against 40 different sides in the Champions League with a superb 22nd-minute strike, but a Danilo Pereira own goal ensured the teams went into half-time level.
Despite the French champions having the better chances in the second half, they failed to find a winner as they took just a point back to Paris, though they remain top of Group H on goals scored.
PSG have now won just once in their last seven away Champions League matches and are without a clean sheet in their last 11 games in the competition, and Galtier told RMC Sport: "There is a feeling of frustration among the players because they have made a lot of effort.
"We had chances in both periods, even if Benfica had some in the first period and that our goalkeeper was busy and efficient. They were quite dangerous.
"We had a fairly good technical mastery with a lot of people up front. In the first half, we didn't have many chances, even though we scored a wonderful goal.
"In the second half, we asked the boys to have more mobility, more depth and more input from the wings. We had a good second half."
PSG finished with 15 shots to Benfica's eight and completed 700 passes, yet for all their firepower were held firm by the team that will visit Parc des Princes next week.
Messi appeared to be a possible doubt for the return fixture, when he made way with 10 minutes remaining for Pablo Sarabia despite PSG chasing a winner, but Galtier eased any fears of an injury.
"After making a sprint, he [Messi] felt tired," Galtier added. "He came off because he felt tired and a fresh teammate was much better at that moment in the game."
With the World Cup in Qatar starting in a little over six weeks, European football's biggest clubs are experiencing an even tighter schedule than usual.
While acknowledging the season is a unique one, Galtier warned his players are paying the price for the congestion.
"It's a very special season, there is fatigue, breakage," he added. "Today we lost Nuno Mendes and we realize that, in this overloaded calendar, there are a lot muscular incidents and injuries."