A moment of brilliance from Isaac Olaofe with just under twenty minutes left gave Sutton a fourth win in five away games and a second consecutive win at Prenton Park.
Olaofe dispossessed home captain Peter Clarke on the edge of the Tranmere penalty area before shooting in to the net, and while it was tough on Clarke, who had rescued his team on three occasions previously, to be the fall guy it was a deserved win for U's who came closest to scoring prior to the goal and then defended well as Tranmere tried to avoid a third successive league defeat.
U's were able to welcome captain Craig Eastmond back after injury, and started brightly, with Olaofe showing his threat early on as he turned away from Jay Spearing thirty yards out and was brought down by the experienced midfielder who took a booking for the team, his fifth of the season triggering a suspension, as Olaofe seemed to be away. Tranmere then had a spell of pressure that produced a series of corners, all of which were well defended, and they came closest midway through the half when Calum McManaman's shot from the edge of the area had Dean Bouzanis scrambling across his goal but bounced wide of the keeper's right hand post.
A well balanced game opened out towards half time and Sutton found space to create chances, with David Ajiboye wriggling his way through a succession of challenges and crossing to the far post, where an unmarked Will Randall saw his header back across goal come back off the upright. Moments later Ajiboye had even more space and took on Calum McDonald on his outside but was forced slightly off balance and sliced his shot wide of the near post. Before the break Peter Clarke was required to make a fine intervention to prevent Olaofe reaching a Joe Kizzi cross after Randall and Ajiboye had again cut open the home defence, but this time Tranmere immediately countered and Liam Feeney ran at the U's defence before, like Ajiboye earlier, slicing a shot wide of the near post under pressure from Ben Goodliffe.
Sutton came out on the front foot after the break and, after Randall had sent a shot just too high from the edge of the penalty area, came very close to going in front when Ben Goodliffe headed Rob Milsom's free kick back from the right and Coby Rowe's volley beat Ross Doohan but was superbly cleared off the line by Clarke. The home captain denied U's again soon afterwards as Richie Bennett battled through on the left and Clarke dived in to divert his shot wide for a corner.
At the other end Coby Rowe produced an equally fine piece of defending to block a shot from Paul Glatzel who had beaten the offside flag on the left and cut in to the penalty area, and Elliott Nevitt dived to meet a cross from Josh Dacres-Cogley but saw his header fly just wide. With twenty minutes to go Clarke went from his side's saviour to villain as Olaofe's persistence saw him chase the defender down as Tranmere tried to play out from the back, win the ball and turn back in to the area before shooting past Doohan with the aid of a slight deflection off Nathaniel Knight-Percival.
It was backs to the wall for U's as Tranmere pushed for an equaliser, but again the defence stood solid and restricted the opposition to few chances, Bouzanis making an awkward save at the second attempt from a McManaman volley, and McDonald's low shot from the edge of the area just evading the onrushing Glatzel on the edge of the six yard box. Bennett was shown a yellow card for taking too long to leave the pitch as he was replaced by Craig Dundas, joining Goodliffe in the book after referee Will Finnie ruled he had dived under a challenge from Knight-Percival, but for the third game running U's back line remained secure and one goal was enough for a victory that saw U's out of the play-off positions only on goal difference.
Sutton: D Bouzanis, J Kizzi, R Milsom, C Rowe, B Goodliffe, A Smith, D Ajiboye, C Eastmond (sub K Davis 88), R Bennett(sub C Dundas 82), I Olaofe(sub D Wilson 75), W Randall. Subs n/u B House, B Wyatt, L John, R Korboa. Booked: Goodliffe, Bennett.
Tranmere: R Doohan, J Dacres-Cogley, C McDonald, N Knight-Percival, P Clarke, C McManaman, K Morris(sub P Glatzel 64), J Spearing, E Nevitt, R Watson, L Feeney(sub J Hawkes 58). Subs n/u J Murphy, T Davies, M Duffy, S Foley, N Maynard. Booked: Spearing, Knight-Percival.
Referee: Will Finnie