The Jags ended their long winless run with a 2-0 victory over Hearts last weekend as they collected their first three points since seeing off Inverness in October.
After a solid start to the campaign, Archibald's side have slipped to 10th in the table and face fellow relegation play-off spot rivals Ross County this afternoon.
Thistle have won admirers for their free-flowing approach on their return to Scotland's top tier this term.
And defender O'Donnell has hailed boss Archibald for keeping a cool head in the heat of battle.
He said: "It is the gaffer's first job. I have not experienced too many runs like that but the gaffer has been great. Everyone sees things differently, but it was good from where I was. He has not changed much and has been working hard.
"We knew it was going to be tough over Christmas, but we have played the football that got us a lot of fans over the first few months.
"I think he kept his nerve. Maybe if you know him socially it is different, maybe his wife will tell you that he is not sleeping and hasn't spoken to her in months! I know I do that sometimes with my girlfriend.
"He has been fine with us. The frustrating thing for us is that, although we have been getting beaten, we have been playing well. It would be easier to come in and shout at us and tell us we are rubbish.
"In a lot of the games, we have more than competed.
"All teams have had to cut their costs, but we have got a small budget compared to the rest and I think we are competing very well.
"Surely the board wouldn't have put any pressure on him but there are crazy things that happen in football."
Victory at Tynecastle last weekend moved Thistle 20 points clear of bottom-of- the-table Hearts and seemingly consigned the beleaguered Jambos to Championship football next term.
While 12th place may be all but confirmed, the Jags find themselves in a four-way battle to avoid 11th this term, with County, Kilmarnock and St Mirren all in the mix.
The introduction of play-offs has provided a much- needed boost to the SPFL Premiership and Championship and O'Donnell insists it is a welcome addition - even if Partick come a cropper this term.
He said: "I think for Thistle it has maybe fallen at the wrong time, but it had to come in at some point.
"I was playing in the First Division two years ago and we weren't winning the league, Ross County had run away with it, and there was nothing to play for. It must have been hard to come and watch.
"It was hard for players as well. You know that no matter if you win, lose or draw, there is nothing there.
"The play-offs have added excitement to the Championship and it adds pressure on us and the teams around about us to try and get away from it.
"It gives us something to play to try and avoid. If you are in it, which I hope we are not, it gives excitement there as well.
"Everyone would rather get automatic promotion or stay up, but it is a lifeline for teams. If we are in it, hopefully, we will win. But we are looking to push up the league. We are in a fight and, hopefully, we can keep pushing on."
Meanwhile, Jags signed Gary Fraser on a two-and-a-half year deal last night.