Arsenal took an emphatic three-goal lead against Anderlecht in Tuesday's Champions League clash at the Emirates, but were ultimately pegged back to 3-3 by their Belgian opponents, the equaliser coming in the final minute of the game.
The visitors had the first concrete chance on goal nine minutes in when Dennis Praet's shot from distance deflected off Per Mertesacker and into the Gunners' side-netting.
Arsenal then threatened three minutes later when Calum Chambers picked out Aaron Ramsey, but the Welshman's effort found itself blocked by Chancel Mbemba.
The game continued to provide high-octane action when, just moments later, Anderlecht marauded into the hosts' final third once again and saw Sacha Kljestan's chance well saved by Wojciech Szczesny.
Arsenal broke the deadlock in the 25th minute when Danny Welbeck won a penalty, which Mikel Arteta duly dinked down the middle from the spot.
Just four minutes later, Arsene Wenger's charges doubled their lead, with Sanchez smashing a rebounded free kick home from the edge of the Anderlecht box.
Early on in the second half, the Gunners were looking at being on the giving end of a rout when Alex Oxlade-Chamberlain swerved past Anthony Vanden Borre into the visitors' box before slotting the ball into the bottom corner beyond goalkeeper Silvio Proto.
However, the former Portsmouth man made amends moments as later he tucked home from close range following a slick pass from Andy Kawaya to sully Arsenal's clean sheet.
The Belgian outfit then pegged the Gunners back to just one goal in the 73rd minute when Aleksandar Mitrovic was brought down by Nacho Monreal in the box, prompting the referee to award a penalty. Vanden Borre stepped up and duly sent Szczesny the wrong way to set up a nervy finish at the Emirates.
The comeback was completed when Mitrovic lashed a header into the bottom right corner to stun the home crowd, who were cruising with just 30 minutes left.
As a result, Arsenal have not secured qualification to the second round of the Champions League just yet - they will need one point from their final two games to book a place in the last 16.
