Wycombe Wanderers opened their Championship season against Rotherham last September and were dealt a bitter blow in injury time.
The Millers broke the deadlock in the 92nd minute to give the visitors all three points.
Now the Chairboys will be looking for revenge in the reverse fixture on East Monday at the New York Stadium following their win against Blackburn Rovers.
READ MORE: Why did Wycombe set up with three at the back against Blackburn? - The boss explains why
Rotherham are currently in the relegation zone with Wycombe looking for another three points, especially against their relegation rivals.
Ainsworth said: “It was a very tight game, it was not billed as a classic.
“Two teams that come up from League one, both renowned for getting the ball forward quite quickly,
"We both sort of cancelled each other out until that last corner in the last minute.
“I still feel the pain of that. It was a tough one to take.
“We had a couple of chances in the game where we could have gone ahead.”
The Wycombe boss believes it would be an “outstanding” achievement for any of the teams that came up from League One last season to retain their Championship status.
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He continued: “It is a fantastic achievement for us both to be in this league and we're both fighting hard to stay in this league.
“Obviously Rotherham are a little behind bit higher than us, but it will be an outstanding achievement for any of the three teams that came up to stay in the championship for successive seasons.”
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