Sunday's 1-1 draw with Lyon extended PSG's unbeaten start to the season in all competitions, but the French champions have not won since thrashing Saint-Etienne 5-0 last month.
Laurent Blanc's men sit three points adrift of early Ligue 1 leaders Marseille, and were held to a 1-1 draw in last week's UEFA Champions League opener against Ajax.
Edinson Cavani's third league goal of the campaign looked to have given PSG all three points on Sunday, but Samuel Umtiti earned Lyon a draw with an 84th-minute equaliser.
And Sweden captain Ibrahimovic, who has not scored in his last four games for club and country, has urged PSG to up their intensity to turn draws into wins.
"We were unlucky today we should have closed the game [out]," he said. "But we didn't and then we concede a goal in the last five minutes.
"We tried to score [to make it] 2-1 but we didn't succeed.
"So we need to work hard and come back."
‘Sir Alex told Van Persie to watch my goal back at Anfield for some shooting tips! It was a beautiful goal, though. It’s a shame that I didn’t do it more often’: Manchester United cult hero recalls stunning strike against Liverpool
‘So many times when we played Manchester United, arguments would start before the first whistle had even blown – the players would try to kill each other with their eyes’ Former Arsenal star remembers famous Premier League rivalry
