Gareth Southgate risked benching Stewart Downing and skipper George Boateng, while still fielding a strong side.
It was a typical cup day match, with winds high and temperatures low.
The area behind Mansfield's dug-outs, which is terrace, was ruled unsafe, and were thus boarded up for the match.
Lee Dong-Gook was the goal scorer at the 17th minute, but even that couldn't save him from being subbed out. He missed easily three other opportunities that should have been put away.
The best chance came at 38 miutes when Jeremie Aliadiere pulled the ball back and he headed it wide from six yards.
Lee was subbed eventually for Stewart Downing. The English international was the deciding factor in the final goal.
Pogatetz, who had a strong challenge on Mansfield's Dawson, was eventually subbed at half to bring on Boateng. The phsyio said he was injured, but I'm sure Southgate really wanted all three points.
Boateng stuck a lofted cross which was on it's way to Downing, but Mansfield defender Buxton got to it first, heading it into his own net. Either way, it looked to be going in.
Mansfield had their chances though. Boulding, easily their offensive player of the match, came closest on 35 minutes. Bouldings left foot effort crashed off the bar, and out of danger.
It resulted in a corner kick, where Boulding climbed the highest, but forced a leaping save from Shwarzer to clear it from under his own bar.
Huth, who was seen double teaming Boulding with Wheater, was awarded the first yellow of the day for a studs up challenge on Boulding. We've seen reds given for less this season, and video replay showed that it was a harsh challenge.
The referee was not in the mood to give penalty kicks and denied both sides from challenges that took down their players in either box.
Boro will ride their luck into the fifth round mounting their fourth round victory, but Mansfield can be proud of their work effort and the heart they put into the game.