Glasgow – Rangers manager Steven Gerrard was furious with referee Willie Collum as his first taste of the Old Firm derby ended in a 1-0 defeat to Celtic and handed Brendan Rodgers first blood against his former Liverpool captain.
Gerrard felt Tom Rogic had fouled Ryan Jack in the build-up to Olivier Ntcham's match-winner, as he was beaten for the first time in his fledging managerial career after 13 games.
"It's a foul. The referee has ignored it and they go and score," said Gerrard. "It's also a foul for the fourth official whose shouting down his mic 'foul, foul, foul' and the referee has ignored that advice."
However, even Gerrard admitted his side deserved little more. Celtic dominated throughout and hit the woodwork three times before Ntcham finally broke Rangers' resistance just after the hour mark.
Victory extended Rodgers's excellent record in Old Firm derbies to 10 wins and two draws in 12 encounters.
But despite not racking up the similar score to a series of routs in the past two seasons, this was arguably his most significant derby win after the first signs of turbulence in his reign following two years filled with success.
Celtic 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 transfer window on Friday.
However, they already enjoy a four-point lead over Rangers and closed to within three points of early pacesetters Hearts.
"We were the very dominant team from start to finish," said Rodgers.
"Steven (Gerrard) has done well getting them organised so we had to be patient. The scoreline doesn't really reflect our dominance.
"We showed a calmness to play round them and play through them. Our only complaint is not scoring one or two more."
Rangers were looking to win at Celtic Park for the first time since 2010 and in high spirits after reaching the Europa League group stages on Thursday.
But a return of just five points from their opening four fixtures is Rangers' worst start to a league season since 1989/90.
Gerrard, though, insists progress is being made and hopes that will be born out by the time the sides meet again at the end of December.
"In 14 weeks we've had a lot of hurdles, a lot of challenges, the boys have given me everything so I can't be too critical," added Gerrard.
"I've seen enough today to feel if we can get bodies back, new signings up to speed, I believe we can be a match for Celtic, particularly in the next fixture.
"Rangers have been 'blown away', 'annihilated', scorelines that are not acceptable in this game. I'm not saying 1-0 is acceptable, but I've seen enough today to say we are working in the right direction."
Twice the woodwork came to Rangers' rescue as James Forrest drilled a stunning volley from 25 yards off the top of the crossbar before Mikael Lustig nodded against the bar.
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 when he headed straight at 'keeper Allan McGregor, who, four minutes into the second half, turned a low Ntcham drive against the bar.
Rangers were finally undone in controversial circumstances when Rogic robbed Jack inside the Celtic half.
From there the hosts were clinical as Rogic, Edouard and Forrest combined to tee up Ntcham for his fourth goal of the season.