Boxing: 'Crazy' Chisora can produce a shock unless Haye hits the heights

Dereck Chisora understands that when he fights his former hero, David Haye, he will start as both the underdog and the bad guy in a fight that has gone from inconsequential at the start of this year to essential tonight.

The two very different boxers will meet over 10 rounds at Upton Park in front of an anticipated crowd of 40,000 and the diverse styles and lifestyles of the two men have added to the attraction of a fight that was made a reality once the pair scrapped at a press conference in February.

Haye has lost just twice in a glittering ring career that has rewarded him with millions for his six high-profile world-title fights, and he appears to have the neutrals on his side in a fight that has been easily crafted as the latest Good vs Evil encounter.

The Zimbabwe-born Chisora has stopped trying to lose his pantomime image as a bad guy, a lunatic in the sport, and has instead played the role to perfection. "I feel crazy today, I forgot to take my medication," he said, earlier this week.

Chisora is not on medication for his erratic behaviour.

Haye is 31 and much lighter but has the longer reach and is about the same height. He has mixed with and beaten good fighters. Chisora's main fighting claim is a trio of 12-round defeats during the last calendar year. It should be a simple win for the former world champion, who boxed beautifully in 2009 to beat Nikolai Valuev for the WBA world heavyweight title, in a fight where he conceded 99 pounds and 12 inches.

However, Chisora has a dangerous combination of bravery and ring arrogance – he is often referred to as being "stupid", and that makes him dangerous.

He has also fought 42 rounds since Haye's last fight and in heavyweight currency that is gold. Haye will need another stunning performance to avoid a shock.