Leon Johnson scored six minutes into stoppage time to earn 10-man Wycombe a draw and deny Scunthorpe a place in the League Two automatic promotion places.
Deon Burton scored his first goal in 12 games to give the visitors the lead, before Wycombe's Josh Scowen was sent off for two late tackles.
Home goalkeeper Matt Ingram denied Sam Winnall and David Syers to keep his side in the hunt.
And Johnson then headed in at the death to the delight of the home fans.
VIEW FROM THE DRESSING ROOM
Wycombe manager Gareth Ainsworth told BBC Three Counties Radio:
"I thought the lads deserved it (the late goal), 10 men worked really hard to get something at the end and chucked everything forward.
"Josh Scowen's red card, I've had a right go at him. I think it's reckless, I think he's stupid getting sent off, and he knows it. He's down, but he'll learn from that.
"It feels like a win, but I'm angry because we had chances in the first half and didn't convert, and just a couple of bad decisions.
"Two big players injured and a suspension. But this is football and I love my job. I'll be in on Monday morning trying to try out how I'm going to do things against Northampton [next Saturday]."
Scunthorpe caretaker Russ Wilcox told BBC Radio Humberside:
"I've got to look at the bigger picture - 10 points out of 12 in the last four games, three away games out of four; the only disappointment today for me was the officials.
"I suppose the other disappointing thing is that we've not managed to finish them off.
"We've had two or three chances at the other end to kill the game, but it wasn't to be today.
"We have to give them credit because they kept on going until the end."
Wycombe Wanderers 01 Ingram 23 Arnold Booked 19 Hause 04 Scowen Dismissed after an earlier booking 05 Stewart 06 Johnson 12 Cowan-Hall (Kuffour - 60' ) 08 Lewis 29 McClure (Morias - 88' ) 20 Craig (Morgan - 42' ) 11 Wood Substitutes 07 Morgan 10 Bloomfield 13 Horlock 17 Morias 18 Kuffour 22 Kretzschmar 28 Knott Scunthorpe United 01 Slocombe 02 Ribeiro Booked 18 Nolan 04 McAllister 05 Mirfin 06 Canavan 14 Hawkridge 24 Syers 29 Winnall 08 Burton (Spencer - 88' ) 16 Adelakun (Williams - 52' ) Substitutes 09 Iwelumo 10 Esajas 13 Severn 15 Waterfall 25 Boyce 28 Spencer 30 Williams
Ref: Fred Graham