The Liga side needed a long range effort from Greek full-back Yourkas Seitaridis in the second-half to claw themselves back into the tie after Dorel Zaharia and Cosmin Tilinca had put the Romanian minnows 2-0 up at the break.
Serie A outfit Sampdoria faired better however, as an own goal from Daniel Dimov helped them earn a 1-0 away leg victory over Bulgarian side Cherno More.
Lens, playing their first competitive game under legendary former Auxerre coach Guy Roux, were second best for long periods in their game against Ukrainian side Chornomorets Odesa but came away with a decent 0-0 draw.
Bundesliga outfit Hamburg also looked rusty and needed a second-half penalty from Dutch international Rafael van der Vaart to earn a 1-1 draw with Moldovan club Dacia Chisinau
In other matches, Otelul Galati of Romania beat Turkish side Trabzonspor 2-1 at home; Gent and Danish side AaB Aalborg played out a 1-1 draw in Belgium; and Rapid Vienna earned an impressive 3-1 home victory over Russian team Rubin Kazan.
England's representative in the competition, Blackburn Rovers, are in Lithuania where they will take on Vilnius Vetra on Sunday.