The Latics slumped to a disappointing 3-1 Premier League defeat at Blackburn on Saturday and remain firmly entrenched in the relegation battle at the foot of the table.

They are just five points clear of the bottom three and still have tricky looking games against Chelsea, Tottenham, Aston Villa and Manchester United to come in their remaining seven league fixtures.

With a mounting suspension and injury list also ruling out a number of key players heading into the crucial run-in, England international Heskey has warned his team-mates that they must raise their game in the coming weeks if they are prolong their three-year stay in the top-flight.

"Being able to battle is the key and when you are in the position we are in, you have to do just that," the striker told the Manchester Evening News.

"It's tough but that's the way we have to do things because we don't have a Cristiano Ronaldo or anyone like that at the club to influence games.

"We didn't quite get it right at Blackburn, so we must now go to Portsmouth (on Saturday) and try to get three points. In the last few games we have battled and we have got ourselves into a reasonably good position, better than we were a couple of months ago.

"It's now so important we keep that up over the remaining seven games in order to reach the target set by the manager.

"We didn't get off to the best of starts at Blackburn, conceding early on but when we equalised the plan was to go in at half-time level and regroup but conceding again was a big blow.

"When Blackburn went down to 10 men, they put three men in the centre of midfield against our two and this made it difficult for us.

"On a positive note, I was pleased to see my fellow striker Marlon King getting on the score sheet because we've both been working hard up front sometimes without any reward but as long as we stay up, that will be our best reward."

Heskey also revealed that he is refusing to get too downbeat about being left out of Fabio Capello's England squad to face France on Wednesday, and is instead focusing all of his efforts on helping Wigan pick up as many points as possible between now and the end of the season.

"You want to play for your country and it's disappointing not to be involved but I'm very happy here at Wigan and that's all I'm concentrating on right now," he said.