Celtic have moved into what appears to be an unassailable lead at the top of the Premier League and at the same time cast a giant shadow over the future of Rangers manager Dick Advocaat.
The champions' and champions-elect's 2-1 victory in the second Old Firm fixture of the season was barely merited but the consequences may be enormous for their old rivals nevertheless.
While Martin O'Neill's team bask in the glory of this win, these are worrying times for the Ibrox club in general and Advocaat in particular. He knows before November is out that the one Champions League place for Scotland next season has been all but secured by Celtic.
To add to his current woes, he became embroiled in a remarkable touchline row with Michael Ball that could spell the end of the former Everton defender's brief sojourn in Glasgow. Furthermore, Rangers' striker Shota Arveladze appeared to racially abuse Celtic's Frenchman Bobo Balde. Advocaat, who has said he would announce his future plans around Christmas, may now call it a day.
The Dutchman, who claimed he did not see the incident involving Arveladze and Balde, admitted: "Ten points is a lot and I can't see Celtic dropping many. It is difficult but everything is possible."
Asked about the incident involving Ball, who was replaced by Peter Lovenkrands, Advocaat said: "Ball was angry but that is good. I was angry too. Players don't want to be taken off but I don't like that kind of reaction from players." Ball and Advocaat appeared to push each other when the substitution was made and the player seemed to swear at him.
Celtic manoeuvred themselves into a strong title position with a hard-fought win in a match littered with drama and controversy.
Rangers began the brighter of the teams and in a frenetic start Rab Douglas did well to touch over a Maurice Ross volley, Ball was booked for a foul on Henrik Larsson and Celtic pair Lubo Moravcik and John Hartson were also shown yellow cards for challenges on Arveladze and Ball.
The first moment of genuine controversy came a minute from half-time when Balde caught Arveladze with a gentle slap, the Georgian went down in a heap and much interest will now focus on what television replays caught him saying to the defender.
Celtic took the lead when a Stilian Petrov free-kick after 58 minutes was knocked down by Balde and Joos Valgaeren, an injury doubt before the match, slid in ahead of Arthur Numan.
Claudio Caniggia replaced Arveladze just in time to see Bert Konterman clumsily push Larsson to the ground, giving the Swede the opportunity to make it 2-0 from the penalty spot.
Jackie McNamara went on as substitute for Hartson and Lovenkrands took over from the irate Ball before referee Stuart Dougal got into the swing of things by flashing first a yellow and then a red card at Konterman for a foul on Shaun Maloney only to realise he had not booked him during the penalty drama even if he perhaps should have.
O'Neill admitted to nervous moments late on, but Celtic were celebrating at the end of another momentous derby.
CELTIC: Douglas, Balde, Mjallby, Valgaeren, Petrov, Lennon, Lambert, Moravcik (Maloney 56), Petta, Hartson (McNamara 70), Larsson. Subs Not Used: Gould, Thompson, Crainey.Booked: Moravcik, Hartson. Goals: Valgaeren 58, Larsson 70 pen.
RANGERS: Klos, Ross (Dodds 81), Amoruso, Konterman, Ball (Lovenkrands 73), Reyna, de Boer, Ferguson, Numan, Flo, Arveladze (Caniggia 64). Subs Not Used: Christiansen, Wilson. Booked: Ball, Ferguson, Konterman. Goals: Lovenkrands 77.
Referee: S Dougal (Scotland).
