Arsene Wenger’s team were left shell-shocked as Geoffrey Kondogbia put the French club ahead with a deflected first half strike before former Tottenham forward Dimitar Berbatov marked his return to north London with the second goal after the interval.
Berbatov’s cool finish was a hammer blow to the Arsenal fans who had jeered him for his past allegiance to their bitter rivals and there was worse to come.
Alex Oxlade-Chamberlain had just given Arsenal renewed hope with a 90th minute goal when Yannick Ferreira-Carrasco galloped clear to score Monaco’s third and leave the Premier League team needing a herculean effort in the second leg on March 17 to avoid last 16 elimination for a fifth successive season.
It was an especially chastening evening for Wenger, who made his managerial reputation during a seven-year spell at Monaco and was renewing acquaintances with his old club in a competitive match for the first time.
After losing to Bayern Munich, Barcelona and AC Milan at this stage, a Monaco side only fourth in Ligue 1 seemed to represent a good opportunity for Arsenal to advance to the last eight at last.
But Monaco had conceded just one goal in their six group matches and Leonardo Jardim’s side produced a counter-attacking masterclass to leave Arsenal impotent in attack and incompetent in defence.
After a frenetic opening, Arsenal found themselves entangled in Monaco’s defensive web.
Alexis Sanchez has emerged as Arsenal’s creative fulcrum in his debut season and the Chile winger almost found the key to unlocking the obdurate Monaco rearguard when he exchanged passes with Mesut Ozil before flicking his shot just over.
But, emboldened by the ease with which they had kept Arsenal at bay, Jardim’s team began to push forward with more confidence and Joao Moutinho found space for an acrobatic volley that sailed over.
– Perilous situation –
It was a warning that Arsenal failed to heed and the visitors went ahead in the 38th minute.
Danny Welbeck lost possession inside his own half and Moutinho quickly moved the ball onto Kondogbia, who had been left unmarked 30 yards from goal.
The French midfielder advanced unchecked before lashing a fierce drive that took a big deflection off Per Mertesacker and flashed past wrong-footed Arsenal goalkeeper David Ospina.
Arsenal still had time to remedy their perilous situation and Olivier Giroud should have equalised early in the second half when he met Sanchez’s cross, only to scuff his shot wide from close-range.
Giroud was presented with an even better opportunity moments later but ended up pounding the turf in frustration after ballooning a header well over from Santi Cazorla’s inswinging free-kick.
And Giroud’s angry reaction was emulated by the entire Emirates Stadium in the 53rd minute when Berbatov doubled Monaco’s lead in stunning fashion.
With Wenger’s side pouring forward in an undisciplined and panicked search for an equaliser, Anthony Martial made them pay, sweeping away down the right before squaring a pass to the unmarked Berbatov, who had time and space to drive a powerful finish past Ospina.
Arsenal needed an immediate response but Giroud’s nightmare continued as he blazed over from close-range after a Sanchez shot was well saved by Danijel Subasic.
Wenger had seen enough and hauled off Giroud, with Theo Walcott on in his place.
Walcott fared no better than Giroud as he failed to beat Subasic from close-range before stumbling and getting in the way of Welbeck’s attempt to convert the rebound.
Oxlade-Chamberlain got one back in the 90th minute when the substitute curled a fine finish beyond Subasic from the edge of the area.
But it was a false dawn as Ferreira-Carrasco was granted the freedom of the right flank to advance and drive a dagger into Arsenal hearts.