Steven Gerrard's first taste of the Old Firm derby ended in defeat as Olivier Ntcham's goal handed Celtic a 1-0 win on Sunday and Brendan Rodgers first blood in his battle with the former Liverpool captain.
Defeat was also Gerrard's first in 13 games as Rangers manager, but on this evidence there is still some work to do for the blue half of Glasgow to end Celtic's dominant run of seven league titles in a row.
The hosts hit the woodwork three times before Ntcham finally broke Rangers' resistance just after the hour mark.
Celtic have endured a turbulent start to the campaign as they failed to qualify for the Champions League, missed out on a number of targets in the transfer window to Rodgers's frustration and sold star striker Moussa Dembele to Lyon in the final hours of the window on Friday.
However, they already enjoy a four-point lead over Rangers just four games into the Scottish Premiership season and close to within three points of early pacesetters Hearts.
Rodgers also extends his excellent record in Old Firm derbies to 10 wins and two draws in 12 encounters.
Rangers had travelled across Glasgow looking to win at Celtic Park for the first time since 2010 in high spirits thanks to Gerrard's impressive start to his managerial career.
That included holding out for a 1-1 draw in Russia against Ufa on Thursday despite being reduced to nine men to make the Europa League group stages.
Gerrard's men were forced into another backs against the wall 90 minutes as Celtic shrugged off their troubles in the transfer market.
- Forrest rattles crossbar -
Dembele had been a constant scourge of Rangers in his two years at Celtic, scoring seven goals in eight Old Firm derbies and his killer instinct was missed as the hosts couldn't turn possession into goals in the first 45 minutes.
Twice the woodwork came to Rangers' rescue as James Forrest drilled a stunning volley from 25 yards off the top of the crossbar.
Seconds later Mikael Lustig nodded against the bar from Ntcham's corner.
Odsonne Edouard deputised for Dembele by scoring twice in a 5-0 rout the last time Rangers visited Celtic Park in May to seal a seventh straight title.
However, Edouard missed Celtic's biggest chance to open the scoring before the break when he headed too close to Allan McGregor.
The Rangers 'keeper was lucky to still be on the field by that stage as an off-the-ball kick to the head of Kristoffer Ajer went unnoticed by the officials.
That decision looked even more crucial when McGregor turned a low Ntcham drive against the bar four minutes into the second half.
Rangers' resistance was finally broken just after the hour mark when for the first time they allowed space for Celtic to counter-attack.
Gerrard was furious with referee Willie Collum for not awarding a foul as Tom Rogic robbed Ryan Jack just inside the Celtic half.
From there Celtic were for once clinical as Rogic, Edouard and Forrest combined to tee up Ntcham for his fourth goal of the season.
Going behind finally brought Rangers out their shell. Alfredo Morelos, who was one of those sent off in midweek, nearly made amends by forcing Craig Gordon into his first serious save at his near post 22 minutes from time.
But their exertions in midweek looked to have taken their toll as the Celtic defence, much criticised in recent weeks, held out.