Lewis Hamilton feels it is time "to go back to the drawing board" in the wake of his latest disappointment.
Hamilton again endured a feeling he dislikes more than any other in a race as he went "backwards" in Monaco, finishing fifth after starting from third, ending up four seconds behind winner Mark Webber. Mercedes's Nico Rosberg was second, followed closely by Ferrari's Fernando Alonso.
Hamilton, who is 13 points adrift of Alonso in the title race, said: "The team definitely have some work to do. I've fallen behind. Race by race we are getting further and further behind the others. I'm still there, but we are falling behind bit by bit, and I've lost a lot of points. We have to focus on trying not to lose any more from now on."
He added: "I have to go back to the drawing board, find out where we are losing time and work on that. It's tough for us, but we will keep pushing, keep fighting."
Hamilton admitted his start was not one of the best, with the 27-year-old just avoiding behind him the early chaos when Lotus's Romain Grosjean collided with Michael Schumacher in his Mercedes, sending the former spinning out.
After that, a slow pit stop in comparison to that of Alonso and Sebastian Vettel resulted in him losing the two places prior to the train-like conclusion to a race in which there was minimal overtaking.
"It wasn't frustrating, but it wasn't the best result," said Hamilton.
"I don't know how long my pit stop was, it was quite a long time, but I wasn't able to keep up with Alonso, and then Sebastian got me in his pit stop. After that it was impossible to overtake.
"I really dislike going backwards, but nonetheless we came away with some points and there are many more races ahead of us, so we have to try and keep our heads up."