Mika Baur celebrates scoring for CelticImage source, SNS

At a glance

  • Baur's first Celtic goal enough to maintain 100% Premiership record

  • Goalkeeper Johnstone makes first start and denies Cotterill

  • O'Neill's much-changed side move five points clear at top before League Cup quarter-final against Rangers on Sunday

ByAmy Canavan
BBC Scotland at McDiarmid Park

Mika Baur's first Celtic goal was enough for the champions to maintain their perfect start in the Scottish Premiership - but they made hard work of inflicting a first home defeat of the season on impressive St Johnstone.

German midfielder Baur was on hand to give a laboured Celtic the lead seven minutes into the second-half as Martin O'Neill's much-changed side failed to hit any great heights at McDiarmid Park.

Despite that, though, they stay five points clear of second-place Rangers at the top of the table.

Though O'Neill made five switches from the side who beat St Mirren on Saturday, the manager insisted this game was more important than Sunday's League quarter-final at Ibrox, but his team delivered a blunt first-half performance in Perth.

For all their attacks - and crosses from Sebastian Tounekti and Haissem Hassan - Celtic struggled to trouble Toby Steward in goal.

Instead, his opposite number, Sam Johnstone - on his first start since joining on loan from Wolverhampton Wanderers - was forced into a superb save to thwart Joe Cotterill from close range.

The former England international had a quieter second half and, although his team-mates were more threatening in front of goal, they failed to make it a more comfortable victory for O'Neill on his first game in Perth for 25 years.

Egypt international Hassan did find the net, but the ball was judged to have gone out of play before Kasper Hogh headed it into the path of the winger.

St Johnstone analysis: Plenty to be proud of

Simo Valakari can once again say this was a performance to be proud of.

Though the attention was on Celtic's five changes, the St Johnstone manager made four of his own from Sunday's win over Hibernian, but you wouldn't know it.

Matty Todd - playing out of position - stood up to the challenge of Tounekti and impressed with debutant Josh Campbell in front of him. The early signs of a decent relationship were promising.

Both were key figures in the disciplined defensive showing, and played their part in the fine showing in attack.

On Sunday, Valakari admitted it'd be "stupid" if his side shifted from the eye-catching, attacking football that won them the Championship last year, just because they were in the top flight.

They would have been forgiven for drifting from it somewhat, given who was in town, but unfazed by the name, they stuck to their game.

It's no surprise now that St Johnstone play good football. And they play good Premiership football.

Celtic had to throw almost every body, and show a bundle of patience, to get their goal. Steward deserves great credit for ensuring it was only one goal with a string of sublime saves late on.

St Johnstone's unbeaten start to the league season here has ended, but when they return here a week on Saturday against Falkirk (19 September, 15:00 BST), they will be favourites.

Graphic

Celtic analysis: Plenty questions for O'Neill

Precision, potency, penetration - none of it was on show from Celtic. Or, at least, by any of the attacking players who started.

Dominant on the ball as ever, they were a frustrating watch in the final third. No one was more frustrated than Hogh.

A striker who plays between the posts - unlike the lively Camilo Duran who was introduced after 73 minutes - the Norwegian was fed very little from his wingers.

Tounekti racked up touches of the ball, and often passed the mismatched test against Todd, but failed at the final hurdle routinely. Lots of balls were swung into the box, but little - if any - of quality.

The Tunisian appears to be a player lacking confidence - in stark comparison to Yang Hyun-jun who has headed off to the Asian Games in great form - often making the wrong decision in front of goal.

Hassan can do magic things with the ball at his feet, but his final product left a lot to be desired.

In making five changes – Johnstone, Dane Murray, Oliver Sorensen, Tounekti and Hogh – O'Neill ought to have been hoping to learn his best pieces in this big jigsaw of a team he needs to pick.

Pre-match, he admitted he had "no idea" what Sorensen was capable of. He might still be wondering.

What he will know for sure, if he didn't already, is that Yang will be an almighty miss; that Duran is his diamond; and there is still a lot of work to be done if his side are to reach the levels he – and supporters – want them to.

A lot of questions to mull over before the small matter of a trip to Ibrox on Sunday.

What they said

St Johnstone manager Simo Valakari: "You play against the champions and big credit to them. That's why they are the champions - they find their way to win these matches, even when it's an even game.

"We created enough chances to get something. That's the disappointment of the evening, that we could not score those. When we keep performing, just taking care of our performances, the results, they will come."

Celtic manager Martin O'Neill: "Delighted to have won the game. Lots to still improve on. A win is a win. I'm not sure what to make of it, really. We could've scored a number of goals, particularly after we scored.

"It's difficult to score goals, there's no question about it. We made it look impossible. We've got to get players into the penalty box to score goals. If you're sitting outside, you'll not get it."

Player of the match

Number: 1 T. Steward
Average rating 8.05
Number: 1 T. Steward
Average Rating: 8.05
Number: 42 R. McAlear
Average Rating: 6.97
Number: 32 J. Campbell
Average Rating: 6.94
Number: 19 D. Finlayson
Average Rating: 6.82
Number: 26 M. Todd
Average Rating: 6.76
Number: 30 J. Cotterill
Average Rating: 6.76
Number: 2 E. Alić
Average Rating: 6.74
Number: 7 T. Steven
Average Rating: 6.72
Number: 3 C. Diabate
Average Rating: 6.65
Number: 18 K. Fotheringham
Average Rating: 6.52
Number: 9 J. Fowler
Average Rating: 6.41
Number: 8 J. Holt
Average Rating: 6.36
Number: 99 R. Paton
Average Rating: 6.30
Number: 22 D. Schmidt
Average Rating: 6.27
Number: 11 S. Stanton
Average Rating: 6.20
Number: 25 M. Tait
Average Rating: 5.97

After the opportunity to rate players has closed, the score displayed represents the average from all the submissions by BBC Sport users.