Stephen Robinson hopes a fitter Jake Hastie can ignite his season after the Motherwell manager admitted his front line was misfiring.

Substitute Hastie's performance gave Robinson some hope after St Mirren inflicted a third consecutive defeat – all at Fir Park – on Motherwell, as they won 1-0 on Saturday.

Jamie McGrath's 13th-minute strike proved enough as the home side struggled to create clear-cut chances following Callum Lang's early miss, although another lively sub, Liam Polworth, headed over from a decent opportunity.

There were half-chances and some strikes from distance and plenty of cleared balls into the box but it was a frustrating day for centre-forward Tony Watt and wide strikers Lang and Christopher Long.

Robinson reverted from a 3-5-2 to his preferred 4-3-3 formation after a raft of injuries left him bereft of defensive options.

Convincing wins over Ross County and Livingston followed but Well have since gone five games without victory, with one set-piece strike from Watt the only forward's goal during that run.

"We have tried to play the three forward players," Robinson said. "We lacked width. For the first time this season we had Jake come on and make an impact.

"So maybe he's an option for us now because we didn't have any width the last two games.

"The three of them all want to play in the one position. I told them to make it work, we have worked on it, and haven't quite made it work yet in the games they have all played together. So we will have to look at that."

Motherwell next take on Scottish Premiership leaders Rangers so Ibrox loan player Hastie will be ineligible, but he could have a big part to play over the festive period.

The 21-year-old started the first two games of the season but was taken off after ineffectual displays and has only made sporadic and brief substitute appearances since August.

But Robinson felt the winger was more like the player who shone before his transfer to Rangers, after he came on in the 56th minute against Saints.

"It's taken us a long, long time to get Jake to where we thought we could get him, through lack of confidence, lack of fitness, and he's been pushing himself over the last few months," said Robinson, who added that an injury which forced Mark O'Hara off after a heavy fall was "not too bad".

"He didn't come to us in good condition, he knows that himself. And that's not me saying that's anything to do with Rangers, he left them in very good condition, but he didn't push himself.

"He has done now and he deserves credit, he came on and gave us the width we haven't had. The other wide players that we have brought on haven't done it, and he gave us a little bit of hope. But we still weren't able to take the opportunities we created.

"Hopefully that might spark Jake into his season."

St Mirren stretched their unbeaten run on the pitch to nine matches, which followed a six-match losing run.

Manager Jim Goodwin always felt they would come good once they got players back and they benefited from a fully-fit squad at Fir Park, with Brandon Mason, Lee Erwin and Cammy MacPherson coming off the bench to help see out the win.

"I've got great faith in this group, even when we were going through that poor period," Goodwin said.

"I always knew when we got the full group back things would turn. And it's no coincidence that we're on this run now because we've kept everyone fit and healthy."