Rotherham extended their lead at the top of League One to nine points with a 1-0 win at Plymouth.
Millers top goalscorer Michael Smith struck in the second half to ensure they took full advantage of second-placed Wigan's defeat.
Argyle's best chance to score fell to Jordon Garrick but his 11th-minute header from a pinpoint Conor Grant cross came back off the post.
Rotherham responded with Ben Wiles letting fly with a shot from outside the box that flew just wide.
Former Argyle striker Freddie Ladapo - who had fired into the side netting early on - forced a brilliant smothering save from home keeper Michael Cooper after 30 minutes.
Garrick had another opportunity to score in the second half but his header flew wide.
And the hosts were made to pay when Smith scored in the 63rd minute.
The striker drilled the ball past Cooper from the right side of the box after being teed up by Wiles, taking his goal tally for the campaign to 18.
Plymouth striker Ryan Hardie was denied by United keeper Josh Vickers in the 78th minute as the Millers held on to complete a league double over their opponents.