A few minutes later, Vrsaljko went in for a late challenge on Lacazette - and Atletico star looked stunned when the referee Clement Turpin shown him a second yellow card, the fifth fastest sending off in Europa League history.
The second leg comes up next Thursday at the Wanda Metropolitano in Spain.
That was until eight minutes to go when Atletico found a potentially-decisive equaliser.
It was all going so well for Arsenal until Laurent Koscielny kicked the ball into his own face...
It was the next-best start that Arsenal could have hoped for, besides an early goal of course.
Heritage Commerce (HTBK) Lowered to Hold at BidaskClub
It improved, as 40 investors sold LRCX shares while 262 reduced holdings. 123 funds opened positions while 558 raised stakes. BidaskClub upgraded Heritage Commerce from a "sell" rating to a "hold" rating in a research note on Saturday, February 24th.