Monaco have given Arsenal a lesson in patient, counter-attacking football to win their Champions League last 16 first leg-match 3-1 in London and take a stranglehold on the tie.
The defeat heaps more European agony on Arsenal boss Arsene Wenger, a former manager at Monaco. Wenger and his team are now facing elimination at this stage of the competition for the fifth straight season after the shattering home defeat.
French midfielder Geoffrey Kondogbia put the visitors ahead after 38 minutes when he crashed in a long range shot that took a deflection off Arsenal defender Per Mertesacker, leaving goalkeeper David Ospina helpless.
Bulgarian veteran Dimitar Berbatov, continually jeered by the home fans because of his links with their arch-rivals Tottenham Hotspur, added the second after 53 minutes after a devastating Monaco counter-attack.
Arsenal pulled one back when Alex Oxlade-Chamberlain curled home from the edge of the area, but Monaco restored their two-goal advantage through Yannick Ferreira-Carrasco, who netted deep into stoppage time.
Arsenal wasted several chances with Olivier Giroud spurning four scoring opportunities to leave Arsenal with a mountain to climb in the second leg in Monaco on March 17th.
Bayer Leverkusen beat last season's runners-up Atletico Madrid 1-0 in Germany courtesy of a fine strike by Hakan Calhanoglu.
The Turkey international scored the 57th-minute winner to set Leverkusen, who are struggling for form in the Bundesliga, on the way to their first ever win at this stage of the competition.
For Atletico, who were left with 10 men when Tiago was sent off following a second booking in the 76th minute, it was only their second loss in a Champions League away game since September 2013.
The Spanish champions will also be missing key defender Diego Godin for the return leg after the Uruguayan was booked and will be suspended in Madrid.