Adam Le Fondre snatched a draw cancelling out Macc's opener just a minute later on a horrible night for football.
The Millers made two changes from the side that had lost to Southend at the weekend for the game with Macclesfield. Captain Ryan Cresswell returned from injury to replace Exodus Geohaghon, whose loan period from Peterborough had come to an end. Danny Harrison replaced the injured Mark Randall.
The Millers started the game with a strong wind and driving rain at their backs, and as early as the fourth minute Le Fondre saw his shot from 25yards skip past Jose Veiga's right hand post.
On 15 minutes Veiga was tested for the first time getting down well to hold on to a Kevin Ellison shot from a outside the box.
The Millers were seeing plenty of the ball but were guilty of knocking the ball long far too many times. It was Ellison again who had a chance on 35 minutes, but Veiga saved comfortably.
The second half got underway with Macclesfield, now with the wind behind them, looking to shoot on sight, and Hamza Bencherif got a fine shot away from 30 yards that skipped along the wet surface, bringing a good save from Andy Warrington down by his right hand post.
The Millers were having much of the ball but were finding it difficult to put any meaningful pressure on Macclesfield, who had the clearest of chances on 76 minutes when with just Warrington to beat Vinny Mukendi missed timed his header from 10 yards.
At the other end, after a strong run substitute Marcus Marshall crossed from the right on 80 minutes, Ryan Taylor getting on the end of the cross, only to sink to his knees after seeing his header thump the bottom of the right hand post.
With just 5 minutes left Macclesfield took the lead when substitute Colin Daniel played Tyrone Barnett through to shoot low past Warrington.
The goal shook the Millers into action and within a minute they were level, Le Fondre finishing off a scramble in the Macclesfield box after Ryan Taylor's replacement Tom Elliott had headed a cross into the area.