Atletico Madrid have not conceded a goal at home in 11 straight games. Arsenal must score a goal there to advance. Hmmm
Salzburg need to over turn a 2 - 0 deficit from the 1st leg , while not conceding an away goal. Altach , Real Soceidad and Lazio have all scored in Salzburg , Marseille are a better side then all 3 imo. Yes there is value in backing Salzburg , but over 2.5 goals seems much more likely.