Hartley bundled home Motherwell’s early opener after Louis Moult’s free-kick had been touched on to the post for his second goal since joining the club on the final day of August.
The Blackpool centre-back signed a loan deal after Motherwell sold Ben Heneghan to Sheffield United and has looked a solid addition in the middle of Robinson’s back three alongside Cedric Kipre and Charles Dunne.
And the 29-year-old showed the type of flair not normally associated with central defenders when he produced a penalty-box Cruyff turn to help set up Ryan Bowman’s 82nd-minute strike in an emphatic victory.
Former Oldham manager Robinson said: “I think that’s the first Cruyff turn Peter has done in his life.
“But working down in England you get to know a lot of the players down there, and Peter was a massive, massive signing for me.
“I have said before, the board were very good. They wouldn’t have sold Ben unless I was able to get Peter so it’s credit to the football club.”
Robinson has also been delighted with Hartley’s’ organisational skills at the back. Thistle never managed one shot on target throughout the game.
“That was probably the one thing we lacked,” he said. “Ben was a quiet boy, an excellent footballer, Cedric is a young boy and Charles is getting his game time up. And Peter pulls everyone about, as well as fitting into the dressing room. He is an excellent fellow.
“We have got boys who will throw their body on the line and we are organised. We are a hard team to break down. We have three big boys at the back and good options out wide.”
Alan Archibald’s side remain without a league win this season and the Thistle boss faces a job lifting his players’ confidence.
They struggled to get out of their own half in the first 20 minutes and looked a beaten team after Craig Tanner swept home Motherwell’s second goal in the 56th minute.
“That was the big disappointment,” said Archibald. “I thought with 30 minutes to go there was a bit of an acceptance there. We have not seen that since probably the first game of the season. That was a surprise.”
The Maryhill side cannot afford to feel sorry for themselves, with bottom club Kilmarnock visiting Firhill after the international break. “It’s huge,” Archibald said. “Including this game, there is a run of games that we knew there were points there to be won.
“The next one at home obviously is huge for the opponents as well.”