Millwall manager Kenny Jackett believed all his side lacked was the finishing touch as they let slip an early lead to lose 2-1 to Doncaster at the Keepmoat Stadium.
David Healy enjoyed a dream debut as his second-half winner secured the points for Rovers in this npower Championship match.
Jackett said: "I thought we had the better chances and it was frustrating we didn't make the most of our opportunities.
"After going in front we had a chance to make it 2-0 and when we were behind we had four more decent chances.
"In fairness to Doncaster they dominated for a 15-minute spell in the second half and that's what won them the game.
"But I thought we deserved to take something from the match. Our spirit was really good and we just needed to capitalise on that and on our scoring opportunities."