Ron Atkinson's team, coming through the hot-house atmosphere of the Avni Aker Stadium, looked to have achieved an even better result after a committed and composed performance, when 12 minutes from time Orhan Kaynak sent a bullet-like header rifling into Villa's net.
'We were excellent in the first half, but in the second half they played considerably better and we played considerably worse,' Atkinson said.
Villa will now attempt to overturn the one-goal deficit in a fortnight's time at Villa Park, just as they did against Inter before beating the holders in a penalty shoot-out.
After surviving Trabzonspor's frenetic opening - with Phil King kicking off his own line from Cengiz - Atkinson's side took a stranglehold on the game.
Harrying and rushing their opponents at every opportunity, and with Andy Townsend overcoming a groin strain to play in midfield, Villa dictated the pace of the game. And with Welsh international Dean Saunders a particular threat, they should have grabbed a priceless away goal after 10 minutes.
Saunders escaped his marker to collect Steve Staunton's pass and crossed to the far post where Ray Houghton had his shot blocked. It fell directly into the path of Guy Whittingham, preferred to Dalian Atkinson, but the striker saw his side-foot effort from six yards cannon away to safety off the underside of the bar.
Two minutes later Whittingham forced keeper Viktor to fumble another Saunders centre, but as Houghton moved in for the kill Unal cleared the danger.
As Trabzonspor responded Orhan, Unal and Lemi were all off target. But seconds after the interval Villa had to thank the same part of the bar that denied Whittingham as Hami struck it with a dipping volley.
Staunton was booked for Villa, though the cautions for Lemi and Kemal could prove decisive as Trabzonspor will be without both defenders for the return match after collecting their second yellow cards of the competition.
Trabzonspor: Grishko; Lemi, Ogun, Kemal, Tolunay, Abdullah, Cengiz, Unal, Soner, Hami (Hamdi, 88), Orhan (Kahi, 89).
Aston Villa: Spink; Barrett, McGrath, Ehiogu, King; Houghton, Richardson, Townsend, Staunton; Whittingham, Saunders.
Referee: M Piraux (Bel).Reuse content