Aberdeen 0-2 Celtic

Celtic reeled off a 10th straight win against Aberdeen - a ninth under Brendan Rodgers - to restore their nine-point lead in the Premiership.

Celtic had Mikael Lustig sent off for a second yellow card 15 minutes from time but Kieran Tierney slammed in a second.

The Dons' frustration boiled over when debutant substitute Sam Cosgrove was sent off for a lunge at Scott Brown.

It left Aberdeen, runners-up for the past three seasons, 12 points adrift of the champions.

Celtic move back nine points clear of Rangers, who they face at Ibrox in a fortnight - after a midweek Premiership game against Dundee and next Saturday's Scottish Cup quarter-final against Greenock Morton.

The champions may not have too many weaknesses but, as they showed in defeat against Zenit St Petersburg in the Europa League on Thursday, they are far from convincing at defending set-pieces at times.

That was certainly the case again at Pittodrie, but Aberdeen failed to exploit the early chances that came their way from a Kenny McLean free-kick, and Kari Arnason's long throw.

Stevie May, preferred to top scorer Adam Rooney from the start, was inches away from converting the first while Anthony O'Connor failed to get enough power on the ball when trying to take advantage of the second.

At the other end, Scott Sinclair's corner clipped the top of the crossbar while Dons goalkeeper Freddie Woodman, on loan from Newcastle, got the chance to show why he is so highly rated midway through the half.

The youngster, who won the Under-20 World Cup with England last summer, made important blocks to deny Sinclair and Dembele in quick succession.

He was also quick to spot the danger as Tom Rogic raced on to a through-ball, Woodman sprinting to the edge of his box to clear the midfielder's header.

He did enjoy a slice of luck after 35 minutes when Olivier Ntcham's sweetly struck shot from the edge of the D smacked back off the post and straight into the grateful arms of the Aberdeen goalkeeper.

There was no let-off two minutes later, though, when Forrest tormented Andrew Considine before hoisting the perfect cross to the back post where Dembele had stolen a yard on Arnason to head home the opener.

Celtic were not at their fluent best, but still had the touch of quality needed to get a victory which again renders talk of a genuine title race redundant.

It proved to be far more frenetic than anyone could have anticipated in an explosive second half that saw both sides finish the match with 10 men.

Lustig had been walking a fine line after being booked for a crude foul on former Celtic team-mate Gary Mackay-Steven and he received a second yellow card after another lunge on the same player with 15 minutes left.

Aberdeen were far more aggressive in the second half as they pushed a higher line and snapped into tackles, but Cosgrove took it too far on what was a disastrous debut for the striker signed last month from Carlisle United.

He was only on the field for eight minutes before receiving a straight red card for chopping down Scott Brown.

But by then Tierney, with a brilliant assist from Dembele, had produced another stunning piece of the quality the ultimately spilt the teams.

The Frenchman ran from just inside his own half as the Dons were caught on the counter-attack, then showed the poise to roll the ball into the path of Tierney who lashed an unstoppable angled drive beyond Woodman.

Aberdeen did have chances to level before that - McLean, Niall McGinn and O'Connor all missed in one goalmouth scramble - but they lacked composure in front of goal.

The painful fact for their supporters is they have now lost all six crunch matches against the Old Firm this season.