The champions are six points behind leaders Hearts, who play Rangers at Ibrox on Sunday, and 25-year-old Scotland midfielder McGregor knows they have to keep the pressure on.

He said: “It is always tough coming off the back of European nights, especially when you get that Thursday/Sunday quick turnaround.

“We had a good game up there (Perth) last midweek. So they will make it difficult for us again.

“We have got to get the freshness in the legs again and go again on Sunday and we need three points.”

McGregor acknowledged that it was a troubling night for the Scottish champions in Austria.

Salzburg reached the semi-finals of the tournament last season, are unbeaten in all competitions this season and have not lost at home since November 2016.

They responded positively from the early setback albeit it took until after the break for the goals to come.

Two in six second-half minutes from Israel international Munas Dabbur and fellow attacker Takumi Minamino put the home side ahead before Dabbur added a third from the penalty spot after James Forrest had been sent off for a foul on skipper Andreas Ulmer.

McGregor said: “They were semi-finalists last year so it shows how good they have been in this competition and they have a really good home record.

“We knew it was going to be tough going there but when you go the goal up everyone’s expectation changes – you can go and win the game or certainly get a draw but credit to them, it was good goals for them.

“It started well for us and we limited them to a few shots in the first half from outside the area.

“They stepped it up and we were a bit sloppy on the ball and caused our own problems

“And then you see how good they are on the counter-attack, the counter press, they get it wide, cross it and flood the box with good numbers and it was good counter-attacking goals.”

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