LONDON (AFP) - Jose Mourinho hopes to sign a "killer" forward in a bid to bolster Chelsea's trophy hopes next season.

While the Blues are still in a three-way fight for the English title, it appears the Champions League semi-finalists will miss out on the Premier League trophy to either Liverpool or Manchester City.

Chelsea manager Mourinho has repeatedly lamented the absence of a prolific front man this season and is understood to want to bring Atletico Madrid's Diego Costa to Stamford Bridge.

Last weekend's 0-0 draw at home to relegation candidates Norwich highlighted Chelsea's problems in front of goal and Mourinho told Chelsea TV on Monday: "Against the teams that are more defensive, more aggressive, more worried about trying to keep a clean sheet than really to play, we keep saying the same.

"We have good players, but we don't have the kind of striker able to, in a short space, to make an action, to score a goal, to open the gate.

"In these kind of matches you just need to open the gate. When you open the gate, the gate is open and you go win much more. We weren't able to do that.

"We have to try to win as a team, to improve as a team, but also add the attacking player with that killer instinct and the number of goals that push teams to different levels.

"It's something our club is going to try (to do), respecting obviously that we have good strikers."

Although Chelsea have won twice against both City and Liverpool in the league this season, recent defeats by Aston Villa, Crystal Palace, Sunderland and the draw with Norwich have cost them dear.

"It's much more difficult to get results against the big teams," Mourinho added.

"Mentally you have to be stronger, by the strategic point of view you have to be stronger too.

"When we have that amazing record against the top teams, I think it's a fantastic achievement and a good base to start next season."