Swindon moved eight points clear at the top of League Two as they edged past fellow promotion chasers Cheltenham.
Darryl Duffy should have put Cheltenham ahead but the striker's penalty, after he was felled by Oliver Risser, was well saved by Wes Foderingham.
Paul Benson stabbed home the game's only goal in the 35th minute from Alessandro Cibocchi's swerving cross from the left.
Duffy looked to make amends but Foderingham denied him twice more.
Away keeper Jack Butland made two superb saves to deny both Benson and Luke Rooney.
Marlon Pack and Jimmy Spencer also went close for the visitors but Mark Yates's side were unable to rescue a point, meaning they lose their place in the automatic promotion spots.
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Swindon manager Paolo di Canio told BBC Wiltshire:
"It was difficult to play at our standards (but) I have to thank the lads because they did an incredible job.
"It was an incredible save from Wes.
"If you want to win the league you have to go through some victories like these, suffering until the end, with many players in a different position.
"We handled the situation, this is the way to win."
Cheltenham Town boss Mark Yates told BBC Gloucestershire:
"I'm the proudest man in Swindon, my players were were unbelieveable. They gave everything. The two best teams in the league were out there - them for consistency, and us. We've battered a good side and not got we deserved.
"Their keeper has made a good save from the penalty and it was a good goal from them, a great ball in and a good finish, but I'm not going to talk about disappointments. I was delighted with the performance, and if we get 10 more of those we'll get where we want to be.
"Darryl (Duffy) must have run over a cat. He had the penalty saved and all the chances seemed to fall to him, but I don't blame players for missing chances. We're in a mini league now over 10 games and we'll try and take care of ourselves."