"His groin's a little bit tight," the Saints boss said. "We'll just have to wait and see. Hopefully, we got it in time and it's not too bad."

The Perth side bounced back from last weekend's narrow defeat by Celtic in resounding fashion.

Guy Melamed scored a brilliant opener from 25 yards, Jason Kerr netted from a rebound just before the break, although there was a clear offside in the build-up. And Melamed hit his fourth goal of the season with a 49th-minute penalty.

Saints had 22 shots to Motherwell's one and looked far sharper in possession throughout with the hosts struggling to even get near the opposition box.

"That was our most complete performance of the season," Davidson said.

"I thought first half we played some real good football in difficult conditions. We cut them open and had some great chances to score.

"Second half I think it was more about a battle and a fight and I think the guys responded really well.

"The attitude of the players was brilliant. I said to the players before the start that it's the league that gets you to cup finals. The league is so important."

Motherwell boss Graham Alexander lost the suspended Stephen O'Donnell, injured Bevis Mugabi and ill midfielders Allan Campbell and Mark O'Hara following their 4-1 defeat by Hamilton and endured a similar afternoon to the previous weekend.

The club listed 12 players on their absentee list and recent signings Harry Smith and Eddie Nolan were also missing from the squad with the bench not filled.

But Alexander declared there could be no excuses and warned his side face a relegation battle.

"It looked like St Johnstone had the heads up on us in every situation – all the duels, the intensity, the game management – and that was a tough one for us to take," he said.

"We have lost some real big players, certainly this week anyway. But we have to deal with that and it's going to be a fight between now and the end of the season.

"I tried to allude to that after the Kilmarnock game. People started talking about what was above and we just had to keep putting points on our tally.

"The last two results have brought that into real clarity, that we have to make sure we win enough points to stay as a Premiership club. Everyone has to have a reality check about this season as a whole and where we are.

"All talk of top six should be put to one side. We are in a fight to make sure we are a Premiership club and we have to show that type of fight, that it means as much to us as anybody else."