St Johnstone made a winning start to their Scottish Premiership return as Kai Fotheringham's strike settled a seven-goal thriller against Kilmarnock.

Both sides held the lead then fell behind at a sunny McDiarmid Park that was witness to plenty of attacking intent but little defensive solidity.

After a year in the Championship, which St Johnstone won at a canter, the hosts unfurled the title flag. They then got off to the perfect start as they took advantage of a Killie mistake to score through Josh Fowler.

Neil McCann's side looked slack on the ball but nabbed an equaliser before the break when Greg Kiltie stole in at the back post to fire home a knockdown.

Just 45 seconds into the second half, St Johnstone were back in front. Cheick Diabate was allowed a free run at a floated corner, powering in his header from a few yards out.

Within two minutes, Kilmarnock were level again. A cross from the right was deflected into the sky and goalkeeper Toby Steward was caught in no-man's land as Joe Hugill got a toe to the ball to loop it into the net.

Less than five minutes later, Kilmarnock had the lead. Nicky Clescenco's shot was initially saved by Steward, but the ball deflected cruelly off Jason Holt and into the net.

The 3-2 scoreline was scarcely believable after the opening 45 minutes, but St Johnstone regained their composure to summon victory.

Louis Lloyd had been on the pitch seconds when he glanced a free-kick into the net - although it was later given as a Michael Schjonning-Larsen own goal.

Then Fotheringham wandered through the Killie defence and into the box where he lashed home the winner.

St Johnstone were rare Premiership casualties in the League Cup group stages and there were some fears from fans before kick-off about the quality of the squad.

Plenty who won the Championship remained - 10 of them started against Kilmarnock - but would they be strong enough to challenge in the top flight?

On this evidence, it's hard to say. Scoring four will normally win you a game, but losing three will normally lose you one.

What's more intriguing is that pre-match, manager Simo Valakari spoke candidly about how his side don't want to lose their free-flowing identity, but have to be streetwise. There was a hint they would be sturdier.

That proved not to be the case. Steward, who was solid last year, made two mistakes that resulted in goals. The midfield, which was in command for most of the first half, was soon made ineffective by a Neil McCann tactical tweak.

However, St Johnstone still had the confidence they could outscore their opponents, and that's what they did.

As for Kilmarnock, McCann spoke of his side's fine defensive record in the League Cup group stage, four games and zero goals conceded.

That was soon shattered as Aaron Tshibola gave the ball away in midfield, with St Johnstone running down the pitch to score.

McCann cut an angry figure for much of the first half. Kilmarnock's passing was sloppy, the errors mounted up, and it looked like the game might get away from them.

When they got level, they soon chucked it away with unbelievably soft defending from a corner. They got another equaliser and then went in front.

However, like everyone else, it appeared they couldn't believe they were ahead and they shipped another set-piece goal before Fotheringham sealed their fate.

Four goals conceded from St Johnstone's xG of 1.76 - that tells you St Johnstone were clinical or Killie were too open. Most who watched would tell you it was the latter.

St Johnstone head coach Simo Valakari: "What a day. It was a big day for the club, to see the Championship flag and play our first Premiership game in front of our fans.

"In terms of the football, we played well today. We're playing against good players, a quality opponent, and they pushed us.

"Welcome to life in the Premiership, from nothing you are 3-2 down. Then you ask what's happening? We have been tested. This is a different level."

Kilmarnock manager Neil McCann: "I didn't find it entertaining whatsoever. We got exactly what we deserved from the game - nothing.

"Can't defend like that, can't play like that and expect to win a game of football."

St Johnstone travel to Paisley to face St Mirren on Saturday, 8 August (15:00 BST) while Kilmarnock welcome Celtic to Rugby Park next Sunday (13:30)