League One leaders Rotherham extended their unbeaten run to 21 games in all competitions with a 1-0 triumph at Cambridge.
Daniel Barlaser's second-half strike made the difference as the visitors maintained their two-point lead over second-placed Wigan.
Dimitar Mitov was called into action midway through the first half when a short Rotherham corner was worked to Shane Ferguson and Mitov beat away his effort from the edge of the box.
A minute before the break, Jensen Weir sent the ball down to Adam May, who strode forward before seeing his low shot saved by Viktor Johansson.
Both sides went close early in the second half, with Joe Ironside firing the ball narrowly wide after being played in by Weir, while - after 52 minutes - Mitov produced an excellent stop to turn away Freddie Ladapo's close-range effort.
The Millers struck the decisive goal after 66 minutes when Chiedozie Ogbene led a rapid break which ended in Michael Smith teeing up Barlaser, who fired precisely into the bottom corner from the edge of the box.
Cambridge's best chance for an equaliser came 15 minutes from time but May could only fire over from distance.