Arsenal, VfB Stuttgart and Olympiakos Piraeus all scored 2-0 away wins in their final Champions League football playoff matches to take a big strides towards the group stage before next week's second legs.
Arsenal became the first English club to win a European tie at Celtic since Nottingham Forest in 1983 with a deflected William Gallas effort and an own goal from Gary Caldwell giving them victory.
Stuttgart won at Politechnica Timisoara in Romania and Olympiakos also scored a good away win and dented Sheriff Tiraspol's hopes of becoming the first Moldovan team to qualify for the group stages.
FC Copenhagen beat APOEL Nicosia 1-0 while Portugal's Sporting had their first goalscorer sent off for celebrating his strike during their 2-2 home draw with Fiorentina.
Montenegro striker Simon Vukcevic earned a second yellow card for taking his shirt off and will miss next week's second leg in Italy.