Martin O'Neill knows Celtic must improve when they meet Rangers after the pair both secured narrow victories in Wednesday's Scottish Premiership action.

Mika Baur's first Celtic goal was enough for the champions to maintain their perfect start in the competition, scraping to a 1-0 win away at St. Johnstone.

It seemed for large parts like Celtic would be punished for a profligate performance, with Sam Johnstone having to make a fine save down the other end to deny Joe Cotterill from close range.

Indeed, Celtic had a massive nine shots on target – worth a significant 2.22 expected goals xG – but were forced to sweat after Baur turned in Haissem Hassan's delivery seven minutes after the interval.

O'Neill will be relieved to add another victory to a fine start, moving five points clear of second-place Rangers before the fierce rivals meet in Sunday's Scottish League Cup quarter-final.

"We can play much better and let's see what Sunday brings," O'Neill said on BBC's Sportsound.

"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. Delighted to have won the game. Lots to still improve on."

Three points secured in Perth #STJCEL | #CelticFC pic.twitter.com/nn0038Y954

— Celtic Football Club (@CelticFC) September 9, 2026

Callum McGregor and James Forrest both passed up chances late on, while Hassan had a goal ruled out after the ball was adjudged to have gone out before Kasper Hogh headed into his path.

O'Neill's focus will now turn to Rangers at Ibrox after Derek McInnes' side left it late to snatch a 1-0 home victory over St. Mirren.

Like Celtic, Rangers accumulated 2.13 xG but only found a way through in the 91st minute when Bojan Miovski's cute chip extended their winning run to four games in the league.

St Mirren could have taken all three points, too, having created the best chance of the clash when Fraser Taylor was sent through one-on-one but denied by Ivor Pandur.

But it was substitute Miovski who stole the show with the winner from Ryan Naderi's flick-on, leaving McInnes delighted.

"I thought we got what we deserved, granted St Mirren had a 20-minute period in the second half when they were better than us," the Rangers boss told BBC Scotland.

"They played with a bit more belief and came after us, and we were guilty of so many poor decisions.

"But I thought the performance for the first hour was really strong, particularly the first half, where we absolutely battered St Mirren.

"I was really pleased with the performance, but at 0-0, as an opposition manager, when you've been put through the wringer, and you know you haven't been punished for it, it does give you power and belief that you can get something from it.

"But I think that the team that had the better chances and played the better football ultimately won the game. There is obviously loads we have to improve on, but we have to keep winning while doing so."