Cambridge United midfielder Ashley Carew struck both goals as the U's saw off Lincoln City at the Abbey Stadium.
Carew fired the U's into a 23rd-minute lead when he brilliantly bent a 25-yard free-kick round the wall and inside goalkeeper Joe Anyon's near post.
Blue Square Bet Premier strugglers Lincoln battled back and were twice denied an equaliser by the woodwork inside four second-half minutes.
But Carew sealed it in injury time with an 18-yarder into the bottom corner.
The U's stretched their unbeaten home run to seven matches in the process, but managerless Lincoln were left cursing when Gavin McCallum's close-range volley struck the bar before another effort from 18 yards hit the post.
Lincoln remain in the relegation zone, in 21st, while Cambridge climb to fourth.
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Lincoln City caretaker manager Grant Brown told BBC Lincolnshire:
"I think the boys have been excellent tonight. We dominated large periods of the game and had the better chances but just couldn't put the ball in the net.
"The free kick we gave away [for the first goal] was avoidable. Set pieces are a tool for winning games and they took their chance, and we have to work harder at not giving away free kicks and also taking our chances.
"There's been a gradual improvement in the performances and tonight was the best of the four [since Brown took charge] and I think there's more in them. They can improve on and take it forward."