A late goal sent Grimsby Town to defeat as Cambridge United snatched all three points at the Abbey Stadium.
In a game where both sides created chances, the Mariners produced a battling performance which had looked like it might bring a reward of at least a point.
But the home side struck a decisive blow with seven minutes left, as substitutes David Amoo and Paul Lewis combined for Lewis to score from close range and win the game.
One change was made to the Town side after last week's defeat at Crewe, with Ben Pringle coming into the starting XI in place of Charles Vernam.
James McKeown began in goal, with Reece Hall-Johnson, Alex Whitmore, Danny Collins and Luke Hendrie in defence.
JJ Hooper, Harry Clifton, Mitch Rose and Pringle were the midfielders, with Elliot Embleton lining up behind Wes Thomas in attack.
Joining Vernam on the Grimsby bench were Sam Russell, Jake Hessenthaler, Jordan Cook, Akin Famewo, Martyn Woolford and Ahkeem Rose.
Cambridge began the day level on points with the Mariners in the League Two table, although one place behind their visitors. The Us had, however, won their previous two games.
The home side made a fast start, creating a chance within a minute as Jevani Brown sent a low cross over for Reggie Lambe, although the striker sent the ball wide of the target.
A number of early free kicks for Cambridge passed without causing any problems for Town, before the Mariners came into the game with a ball from Hendrie into the box which was cleared.
A whipped delivery into the home penalty area was then headed out for a Grimsby corner, although Embleton's delivery was overhit.
Hooper was penalised for a foul after he collided with keeper David Forde as he aimed to reach a ball from Clifton on 14 minutes.
At the other end, Liam O'Neil sent a shot over McKeown's bar after the ball had dropped to him on the edge of the box.
The keeper was called into action on 18 minutes though, diving to stop an effort from Brown.
A free kick five minutes later from George Maris into the Town box was half-cleared and the hosts retained possession until a cross was dealt with by Hooper.
Another free kick came for a foul by Hall-Johnson on the left and again, the danger from it was not fully dealt with, as the ball was returned into the penalty area before being sent out for a goal kick.
Embleton registered Town's first shot on target on 28 minutes as his curling shot was caught by Forde, before a cross from Hooper eventually led to another chance for the Sunderland loanee, whose effort went just wide.
Brown had another opportunity on 34 minutes but watched his curling shot from the edge of the box go narrowly off-target after it had beaten the dive of McKeown.
A cross from Embleton led to Thomas firing over the bar soon afterwards, then the next home attack produced a corner as Jake Carroll's cross was put behind by Hendrie. The ball from the flag was headed off-target by Greg Taylor.
A mistake by Taylor then gave the Mariners a corner at the other end but it was headed clear as far as Whitmore. He returned the ball to Hooper but his header was punched clear by Forde.
A foul by Clifton on Maris gave Cambridge an opportunity to get the ball into the box on 44 minutes and from it, McKeown made a great save to deny O'Neil, whose free header was pushed away for a corner by the keeper.
Two added minutes were played at the end of what turned out to be a goalless first half, with the hosts having created the better chances but the Mariners having opportunities of their own.
No changes were made before the restart and after a scrappy opening to the second half, Town had the first chance when Embleton got the ball on halfway and advanced into the box before shooting at Forde.
The first substitution was made on 54 minutes and saw Famewo replace Whitmore in the centre of defence.
A foul by Pringle on Brad Halliday gave the home side a free kick in a dangerous position and Briwn's ball into the box was cleared off the line and flicked away for a corner.
Brown sent a shot just over McKeown's bar from distance as Cambridge threatened again, before a home change saw Amoo come on for Maris.
A cross-shot from Hall-Johnson led to a corner after a mistake by Forde but the flag-kick did not cause significant problems as the ball eventually went out for a goal kick off Famewo.
Hessenthaler came on for Pringle before a cross from Amoo was cleared by Collins, then a shot by O'Neil was deflected and cleared.
Hooper tried his luck from the edge of the box on 69 mnutes but failed to hit the target, before Hall-Johnson went down under a challenge inside the penalty area but the referee allowed play to continue. The right-back kept possession, although his shot hit the side-netting.
The Town pressure continued when Hooper made his way into the box but his low cross did not find a team-mate.
Harrison Dunk came on for Lambe and Lewis replaced O'Neil as Cambridge made a double substitution.
Soon afterwards, Hall-Johnson went down inside the penalty area again and this time, the referee did take action but it was against the Mariners defender, who was booked for diving.
Brown lifted a shot over the bar after the ball had been knocked down for him by Lewis, then Embleton was denied by a good save from Forde as the game moved into the last 10 minutes with both sides pushing for a winning goal.
Embleton forced Forde into another save with a shot from the edge of the area that the keeper got down to stop.
But soon afterwards, the Mariners fell behind when a low cross from Amoo was turned into the net from close range by LEWIS.
Cook replaced Clifton immediately after the goal as Town looked to rescue something from the game with seven minutes to go.
Embleton was booked for a foul on Dunk, before a Grimsby corner brought a chance to apply some pressure, although it was eventually dealt with by the home defence.
And Cambridge were able to see out the remainder of the game to claim maximum points and send the Mariners to a second consecutive defeat.
Town are next in action on Tuesday, when they travel to Mansfield Town for a rearranged game.
1 David Forde
2 Brad Halliday
3 Jake Carroll
5 Greg Taylor
4 George Taft
8 Liam O'Neil
19 Reggie Lambe
6 Gary Deegan (C)
20 Jevani Brown
18 George Maris
14 Jabo Ibehre
13 Dimitar Mitov
16 Harry Darling
25 Louis John
22 Paul Lewis
15 Emmanuel Osadebe
7 David Amoo
11 Harrison Dunk
1 James McKeown
2 Reece Hall-Johnson
27 Luke Hendrie
6 Danny Collins (C)
25 Alex Whitmore
8 Mitch Rose
22 Elliot Embleton
15 Harry Clifton
39 Wes Thomas
9 JJ Hooper
30 Ben Pringle
23 Sam Russell
12 Akin Famewo
11 Jordan Cook
7 Jake Hessenthaler
16 Martyn Woolford
21 Ahkeem Rose
18 Charles Vernam
Referee: Nicholas Kinseley
Attendance: 4,096 (609)