Tottenham stars celebrated in an unusual way.
Lamela uploaded a video to his Instagram story feed an hour after the final whistle at the Nou Camp.
Tottenham drew 1-1 with Barcelona thanks to a late goal from Lucas Moura.
Inter Milan could only draw 1-1 with PSV, meaning Tottenham went through.
In what we assume is the result of a promise he made if Tottenham qualified, unused substitute Gazzaniga agreed to let Argentine international teammate Gazzaniga shave his hair.
Erik Lamela celebrating Tottenham's CL progress by shaving teammate Paulo Gazzaniga's hair off pic.twitter.com/nVYbIWaXfv— Dan Coombs (@hitcdancoombs) December 12, 2018
Gazzaniga played his role in Tottenham's qualification with an important performance at home to PSV, when Hugo Lloris was suspended.
He has elevated himself to second choice ahead of Michel Vorm, who began Tottenham's campaign in goal away to Inter Milan.
Lamela came off the bench in the 61st minute to replace Kyle Walker-Peters, as Mauricio Pochettino made a tactical shift.
It worked, with Spurs 1-0 down at the time and going on to salvage a decisive point.