Derby moved to the brink of promotion to the Championship after a 1-0 win at Cambridge.
Nathaniel Mendez-Laing’s goal shortly before half-time leaves Paul Warne’s side needing one point at home to bottom club Carlisle next weekend to go up.
Cambridge will be safe if they win either of their two remaining games, or if Cheltenham fail to win both of theirs.
U’s keeper Will Mannion tipped Louie Sibley’s corner onto the bar early on, while at the other end Joe Wildsmith saved well from Macauley Bonne in the 15th minute.
Mendez-Laing nearly scored in spectacular style after 38 minutes, seeing his superb curler from nearly 30 yards come back off the bar, but he only had to wait a few seconds before putting the Rams ahead.
Sibley played Mendez-Laing in behind the defence, and he rounded keeper Mannion outside the box before firing into an empty net.
Cambridge came on strong after the break, with Jordan Cousins firing just wide from distance and Ryan Bennett seeing a shot blocked.
Subscribe or register today to discover more from DonegalLive.ie
Buy the e-paper of the Donegal Democrat, Donegal People's Press, Donegal Post and Inish Times here for instant access to Donegal's premier news titles.
Keep up with the latest news from Donegal with our daily newsletter featuring the most important stories of the day delivered to your inbox every evening at 5pm.