Oldham manager Lee Johnson hailed a "monumental" result for his team after they held on for a 2-1 victory over Swindon.
Lee Johnson: Well chuffed with Oldham
Johnson's side withstood intense second-half pressure to move up to fifth in League One and dent Swindon's automatic promotion bid.
Oldham went ahead in the 10th minute when Conor Wilkinson's right-wing cross picked out Mike Jones for a sweetly-struck finish from 12 yards.
Straight from the restart Swindon gifted Oldham their second goal, with a stray pass allowing Wilkinson to steal possession and run clear before calmly slotting inside a post.
Latics top goalscorer Jonathan Forte had a header disallowed for offside and Rhys Murphy also went close, but Swindon became the dominant force.
Home goalkeeper Jake Kean did well to deny Ben Gladwin and Michael Smith before Massimo Luongo's 20-yard shot halved the deficit after 63 minutes.
Andy Williams and Harry Toffolo had Swindon's best chances to equalise, but Oldham defended heroically.
Johnson said: "It's monumental for us because Swindon are such a good side with a nice philosophy and very good players.
"I'm well chuffed and it shows how far we've come that we have played so well and won the game.
"If we hadn't performed we could have lost by three or four, but we had energy and we took the game to them.
"We had a go right from the start and, although we got deeper and deeper in the second half, that's two fantastic wins in the last few days (after the victory at Scunthorpe).
"It was exciting because you could see the quality of the opposition, but you could also see our own quality and our spirit.
"With this squad we know we'll get results with commitment and passion.
"We work hard every day to get better, but we can't be complacent and we need to follow up by beating Colchester on Saturday."
Swindon remain second in the table, but boss Mark Cooper was furious with his side's nightmare opening to the game.
Cooper said: "We got caught cold. We didn't start properly and we got punished for the first 15 minutes.
"We gave a team a two-goal start and they couldn't believe their luck. I don't know what you put it down to, but we need to learn from it.
"Oldham came out of the blocks quickly, but you can't give the ball away as cheaply as we did in those areas.
"After the first goal we should have had a breather, but we gifted possession and that was asking for trouble.
"When you look at chances and dominance the second half was probably the best we've played this season, but it was too late at 2-0 down.
"I was still confident, but there were gilt-edged chances and you've got to put those away.
"We have four decent strikers, but we were patchy up front and my regret is that I didn't bring Jermaine Hylton on earlier."