Simpson struck a 90th-minute penalty for the visitors who looked all set to leave empty-handed after Joel Grant's 78th-minute strike put the Chairboys ahead.

Filipe Morais and Stuart Beavon, with his 23rd of the season for Wycombe, traded goals in the first half while Simpson's penalty came just six minutes after the Chairboys had missed a spot-kick of their own through Grant Basey.

The visitors took the lead after 14 minutes when Portuguese frontman Morais' right-foot effort from fully 25 yards went in off the post.

But three minutes later red-hot frontman Beavon chipped Ben Strevens' through ball over the onrushing Dean Bouzanis.

Grant put the home side ahead in the 78th minute before the Chairboys wasted a golden opportunity to make it 3-1 from the spot - Basey firing wide. And they were made to pay for that wastefulness when Marvin McCoy pulled down Simpson and the 27-year-old made no mistake from 12 yards.