Hearts were forced to show steely resolve again as they battled past St Johnstone in the Scottish Premiership following their midweek European heroics.

Having qualified for the Conference League with a penalty shootout victory over Rapid Vienna, Wouter Vrancken's men initially showed little sign of fatigue as they raced into an early lead at Tynecastle.

It was gifted to them as St Johnstone struggled to play out from the back, allowing Josh McPake to slip James Wilson in, and the 19-year-old finished first time.

The hosts continued to dominate, peppering shots at the Saints goal, but Toby Steward - the best goalkeeper in the Championship last season - pulled off numerous good saves to deny them.

There was little he could do when a combination of Hearts midfielder Laurent Mendy and Saints debutant Enes Alic bundled a cross in at the back post - the goal ultimately given to the visiting defender.

But Simo Valakari's side weren't going quietly and they were superb in the second half, scoring early when Ruari Paton slipped behind the defend and slid the ball past Beau Reus.

The visitors kept up the pressure but they could find no way past a Hearts side who looked sapped of energy after playing for 120 minutes on Wednesday night.

Outstanding in attack, vulnerable at the back.

It is a recurring problem for new head coach Vrancken, who has spoken of the need to find balance between the two ends of the pitch.

In this win, though, could that simply be put down to fatigue? The depths of their energy reserves had been plumbed in a gargantuan task to overcome Rapid Vienna with 10 men.

Hearts burst out of the traps in the first half, firing off 11 efforts, seven of which were on target. In the middle of the park, Mendy barely put a foot wrong as he came inches away from his first Hearts goal.

That was important, given the nasty-looking injury to Tom Renaud in midweek that could rule the Frenchman out for an extended period.

However, at the back Hearts still looked shaky. St Johnstone scored early in the second half - another goal conceded far too easily.

As the clock wore on, simple passes went astray and the decision-making deserted the hosts. Mental tiredness, as well as physical, crept in and by the end they were hanging on.

But hang on they did. That will boost them before the Edinburgh derby on Thursday night at Easter Road.

Given how the goals were given away, it would have been easy for St Johnstone's heads to go down early on.

That's what happened when Dundee United visited Gorgie a few weeks ago, a game that ended 4-0. This Saints side have more resolve, though.

Valakari's side wrestled back momentum from their hosts and had a few great chances to go level.

That was down to former Hearts man Jason Holt and Sam Stanton's tremendous efforts in the middle of the pitch, as well as the endeavour of Jamie Gullan and substitutes Taylor Steven and Kai Fotheringham.

But there was a lack of composure up front, typified by Josh Fowler's inability to pull the trigger when he rounded Reus in the second half.

All the signs are there though. There's a similarity to Hearts in that they have ability up top, they just need to shore up at the back.

Hearts head coach Wouter Vrancken: "Relieved. The most important thing today is the three points. We knew for some guys, who played 120 minutes, it would be difficult.

"These weeks will come. It's a good learning process. When you play during the week in Europe and perform again two days later, it's not easy. It's good for the players to feel this and know what it brings."

St Johnstone head coach Simo Valakari: "We created enough chances, but if you don't take them, it's hard to win and we didn't. That's the disappointment.

"I like how we played, our players wanted to show themselves. When we found our rhythm, the boys really played, but it's all about the result and we did not get it."