Gary Deegan scored a late equaliser as Cambridge twice came from behind to draw 2-2 at Northampton.
Kevin van Veen put the home side ahead on two separate occasions in the second half but both times the visitors fought back to snatch a point.
The first half mostly belonged to Northampton as Matt Crooks and Andy Williams missed chances, but the first goal did not arrive until 13 minutes into the second half when Van Veen gathered Daniel Powell's pass and smashed the ball into the top corner.
Crooks headed a great chance over the crossbar and he was made to rue that miss 20 minutes from time when George Maris finished coolly into the bottom corner after pouncing on a poor defensive header.
But the home side were back ahead eight minutes later through Van Veen's second as he charged down a clearance and fired home via the underside of the crossbar.
Again Northampton could not hold on, though, and with just four minutes left, Deegan brilliantly curled a shot into the far corner from 20 yards to earn a share of the spoils.