The Firhill No.1 has kept his place in Alan Archibald's side ahead of new goalie guru Gallacher and has enjoyed an impressive start to the season.
But the Jags shotstopper knows he cannot afford to take anything for granted as his mentor eyes up his starting jersey on a weekly basis.
Fox said: "Gall has been really pushing me along. Obviously he wants to play as well so he has got that edge.
"There is a good bit of banter between us and the competitive edge is there as well.
"It has been really good working with him and I am enjoying it very much. Sometimes when we speak it is like he doesn't want to give me the negatives but, as my coach, I would rather he told me what he thinks.
"He has done that and everything he has done has benefited me so far. Hopefully, I can keep him out the team for a bit longer.
"I want to play as often as possible and he knows that but I know that if my form dips then he can come in and he is more than capable of playing."
With two wins and two draws from their opening five SPFL Premiership fixtures, it has been a superb start to the campaign for Archibald's side as they have adapted well to the rigours of top-flight football.
The Jags boss has stuck with the players that took his side to the First Division title last term and Fox reckons familiarity is breeding success at Firhill as they prepare for the visit of Aberdeen a week today.
He said: "Me and the defence are playing well and we are happy. We had a good year together last season so we know how to talk to each other and how each other plays. The whole team has been great.
"It has been a positive start for us. We are doing well in the league and we have got through a couple of rounds in the cup so we are pleased with how things have been going.
"We have got a break because of the international games and we will be raring to go once the league starts again."
With victories over Ross County and St Mirren on Premiership duty and League Cup triumphs over Ayr United and Cowdenbeath to their credit already this term, confidence is high at Firhill as the Jags look to continue their impressive start to the campaign.
The only low point of the season came at Fir Park as they slipped to a 1-0 defeat to Motherwell, condemning Archibald to his first league loss as a boss.
But Fox reckons the Steelmen clash was also a timely reminder of the levels Thistle must maintain amongst our elite teams.
He said: "We always had the confidence we could make a good start. We have that winning mentality coming up from the First Division, we are on the crest of a wave just now.
"The most positive thing was probably getting beaten off Motherwell and then coming back the next week and winning again.
"We were doing well and playing well going into it but the first half there was probably our only negative.
"We got back into the game but still lost and it shows that if we don't start well and go about things in the right manner then we will get beaten."