Anthony Stokes scored the only goal of the game as Celtic overcame stiff Aberdeen resistance to record a second league win that came at a price.
Celtic lost full-back Emilio Izaguirre to a suspected broken ankle after only 15 minutes at Pittodrie.
Kris Commons and Aberdeen's Scott Vernon both tested the respective goalkeepers in an exciting first half.
Vernon failed to connect in front of goal after the break before Stokes powered in the 74th-minute winner.
And the victory puts Celtic one point clear of Dundee United and St Mirren at the top of the Scottish Premier League - and with a game in hand - after two wins, although Motherwell would leapfrog them all should they defeat Hearts later.
Former Cardiff right-back Adam Matthews had been handed his competitive debut for Celtic in place of the injured Mark Wilson, while Daniel Majstorovic was in for the crocked Glenn Loovens.
But it was the Dons rearguard, where the experienced Rory McArdle had replacing Clark Robertson, who were under pressure immediately after kick-off.
A 25-yard Kris Commons drive, pushed comfortably for a corner by on-loan Manchester City goalkeeper David Gonzalez, was the closest they came to making their early pressure tell.
The Dons settled and worked their way into the game, with Darren Mackie's pace worrying Majstorovic.
Peter Pawlett was beginning to give Izaguirre a hard time on the Aberdeen right and a fair but tough challenge left the Honduran writhing in pain before being stretchered off.
Pawlett's enthusiasm was dampened moments later when he was shown a yellow card for a late challenge on Izaguirre's replacement, Charlie Mulgrew.
Celtic responded to the loss of last season's player of the year by re-establishing control and Beram Kayal sent a 20-yard drive whizzing over the crossbar as the pressure built once more.
The Dons threatened on the break and Scott Vernon's low effort from 20 yards was beaten away by goalkeeper Lukasz Zaluska.
Aberdeen survived some intense pressure to go in level at half time and it was Ki Sung-Yeung who was first to go close after the break with a glancing header that flew a yard wide.
Vernon missed an opportunity at the other end when strike partner Mackie flashed a ball across the face of goal and the Englishman failed to connect under pressure from Kelvin Wilson.
A mistake by Richard Foster led to Celtic's breakthrough when the Aberdeen captain was dispossessed by Commons.
Stokes played it wide to the Scotland winger, whose return ball into the middle was blasted low into the net from 14 yards by the Irishman.
Gonzalez did well to save with his legs as Celtic substitute James Forrest was put clear behind the defence, but one goal was enough to give the Glasgow side a win they just about deserved.