Sutton bounced back from Saturday's defeat at Barrow with a flying start that saw U's two up against Crawley inside seven minutes, and although it wasn't always straightforward after that, particularly at times in the first half when Crawley came close to reducing the arrears, it was ultimately enough of an advantage and Ali Smith's second goal of the night, five minutes from time, made sure there was no nervous finish.
The importance of the win became clear as results came in from elsewhere, with Mansfield and Swindon both taking maximum points, and U's may still need to win both remaining games to qualify for the play-offs, but without this victory U's would have been cast more in the role of outsiders.
Looking for a quick start to shake off Saturday's defeat, U's couldn't have asked for more as first Smith drove a superb 25-yard shot left footed past goalkeeper Glenn Morris after the returning Harry Beautyman had intercepted a clearance with his head, and then Richie Bennett produced a neat back-heeled flick to divert Rob Milsom's inswinging free kick in to the net.
The goals settled U's, but Crawley, who had started well before the double blow, came back strongly and Tom Nicholls curled a shot just wide of the far post after cutting in from the left. Moments later, when U's lost possession inside the Crawley half, a quick break saw George Francomb send Ashley Nadesan through, and Dean Bouzanis needed to make a good save. The ball ran loose to Aramide Oteh, but having steadied himself he shot wide of the left hand post.
Sutton had chances before the break to extend the lead, Donovan Wilson's shot deflected wide, David Ajiboye shooting over when slightly off balance after being set up by Will Randall, and Randall himself running on to another delicate flick by Bennett, surging past one defender but shooting against the legs of the advancing Morris. However Crawley had had enough of the game to think they were still in with a chance, and early in the second half Louis John had to block a shot from Oteh at close range.
Apart from long range efforts from Jake Hessenthaler and substitute Isaac Hutchinson, though, which were both well struck but both straight at Bouzanis, the visitors struggled to threaten the Sutton goal and the clearer chances came at the other end. Wilson beat his man on the right before cutting in, but having done everything right he then blazed his shot over the bar. Morris pushed away a Randall cross that would otherwise have presented Ajiboye with a far post tap-in, and Smith shot just over after Ajiboye had beaten three defenders in one turn by the corner flag to set up the chance.
The two combined again with five minutes to go, and this time there was no mistake as Ajiboye ran on to Bennett's header and slipped a pass outside him to Smith, who fired unstoppably in to the roof of the net to round off another impressive home result for U's.
Sutton: D Bouzanis, J Barden(sub K Kouassi 90), R Milsom, A Smith, B Goodliffe, L John, D Ajiboye, D Wilson(sub I Olaofe 78), R Bennett, H Beautyman, W Randall(sub E Boldewijn 81). Subs n/u S Nelson, B Wyatt, C Rowe, K Davis. Booked: Barden
Crawley: G Morris, A White, J Lynch, G Francomb, T Craig(sub M Marshall 69), J Tunnicliffe, J Hessenthaler, A Oteh(sub I Hutchinson 62), T Nicholls, A Nadesan, W Ferry. Subs n/u O Gallacher, L Francillette, T Seymour, F Kastrati. Booked: White, Oteh, Nadesan.
Referee: Sam Allison