Fernando Alonso says if McLaren can make a "two and a half second" gain at the start of 2016, they will return to winning ways.
McLaren's first season back with Honda power has been a wretched one for the partnership.
They have lacked both performance and reliability leaving Alonso and Jenson Button struggling to even get out of Q1.
That has made points very hard to come by with the team scoring just 19 in 15 races.
Despite their troubles, Alonso believes race wins could be on the cards next season.
"Two and a half seconds. If we improve two and a half seconds, we will win next year," he told Motorsport.com.
Pressed as to whether he felt that was a realistic improvement, the Spaniard said: "Yes, I think so. It's realistic but the thing is that we need to work very hard with a very high discipline all winter and all united, because in this new Formula 1 everything is a package.
"It's all combined that makes the perfect car and we are working on that. We have understood that and we are trying our best. It's a very big gap that we have to close.
"Also we need to improve the reliability side a lot, because we cannot forget that we have used 11 engines so far, so this is something that we cannot afford next year.
"So it's many things to put in place, but all the steps and all the actions that the team has taken in the last couple of months are logic and good, and I'm positive."
He does, however, concede that it won't be easy beating Mercedes, who wrapped up their second successive Constructors' title in Sochi.
"Winning is another step. Winning is beating Mercedes, and right now very big teams with the things more or less in place cannot do it, so for us it will be a huge task, but we are ready to try at least."