ESSENDON coach Matthew Knights say this Friday night's clash with Melbourne is a "must win" game if the Bombers want to stay in the hunt for the finals.

The Bombers reached the half-way point of the season at 5-6 and in 11th spot, with impressive wins over Hawthorn, Collingwood and Carlton, but also losses to Port Adelaide and North Melbourne.

Knights said the side desperately needed to step up its performance in the second half of the year.

"We would have to play better football than we have in the first half," he said from Windy Hill.

"At times in the first half of the year we've played some high-quality football, and our highs have been very high, but I think some of our inconsistency ... we've got to massively improve in that area.

"Because at times, we've had inconsistent periods in games, and it's not good enough."

Knights said he would not use injuries or the fact he was fielding such a young team as excuses and said the side would have to improve to make the finals.

Last time out, Melbourne got smashed in the Queen's Birthday game by the Magpies, losing by 11 goals, but Knights warned that the result was an aberration.

"I went to the Queen's Birthday game, and I don't think that was a true reflection on the way they've played the last four to six weeks,” Knights said.

"Collingwood were really hot, they started fast, and Melbourne couldn't recover, but in the previous four to six weeks before that, they were playing pretty good football.

"They'll be desperate to do very well after the Queen's Birthday, so we're expecting that they will come out and play real hard, and it's not going to be an easy game, by any stretch.

"We're going to have to play pretty well, and we're coming off a loss ourselves, which was a disappointing one, so we should have impetus to go into the game as well."

Friday night’s match will also mark the fourth annual Clash for Cancer. Both teams will wear a special guernsey with a yellow band as a show of honour and respect for all those who have survived cancer, those currently facing the cancer fight and to remember mates who have lost their lives to cancer.

Supporters at the game can show their support by purchasing a yellow Call to Arms slap band at the match.