Dean McKay's last-minute goal clinched a 1-0 triumph over leaders Greenock that enabled second-placed Ants to close within five points of Nock and four points clear of the chasing clubs.
Cotter said: "Without getting too carried away, I would think our promotion challenge is very much back on track after beating Greenock.
"What was really pleasing was the manner of our victory because after playing very well in the first half without any scoring reward, the guys showed their battling qualities to eke out a result even though Greenock had shown their qualities by dominating the second 45 minutes.
"The only downside was a very harsh red card dished out to Gareth Timoney for doing nothing other than stopping his team-mates from getting involved in a first half flashpoint. We'll wait and see whether he wants to appeal."
Yet another crunch 90 minutes is looming for the Govan cracks with fifth-placed Neilston scheduled to visit McKenna Park this weekend, however Cotter insists his touchline presence will not be missed while he is on holiday.
He said: "Danny Drew has come into our backroom team and his Junior nous has been used to good effect on the coaching side of things.
"He, along with Bonar McKenzie and John Doyle, will be looking after team matters for the Neilston game and I've no doubts they will get the utmost respect from the players.
"It promises to be a tough contest because Neilston have taken huge strides forward under Andy Whiteford and it speaks volumes of his management that they have only lost one of their last six league matches."
There's a basement showdown in one of the other First Division encounters as Bellshill Athletic's new coaching team of Davie Turnbull and Robert Downs seek to pick up their first points since taking charge when facing second-bottom Port Glasgow.
Meanwhile, there's some festive friendly action taking place tonight with Carluke Rovers meeting Shotts Bon Accord at the John Cummings Stadium (kick-off 6.15pm).
Tony McInally's playing charges suffered a 5-2 defeat on their last visit to Carluke in a Euroscot Eng sectional game back in August, but a desire to cram in some playing action has seen Macca take on what could prove to be a testing encounter.
He admitted: "Match fitness levels are way below what they should be given that we've not played for almost six weeks, so this friendly is coming at an ideal time.
"We know from fairly recent experience that Carluke can be formidable opposition on their own 4G pitch, but the tougher the workout the better as far as I'm concerned.
"Our immediate agenda has difficult cup games against Kilbirnie Ladeside and Benburb over the next three Saturdays, so there's a crying need for players to get in shape and quickly."