Gareth Barry scored on his 400th club appearance as Aston Villa came from behind to defeat ill-disciplined Litex Lovech. Barry converted a 72nd-minute penalty after the Bulgarian Cup holders were reduced to nine men at the Gradski Stadium.
Nigel Reo-Coker scored for the second time in as many games to haul Martin O'Neill's side level on the stroke of half-time after a gaffe from goalkeeper Uros Golubovic.
That mistake altered the shape of the contest and red cards for Cédric Cambon and Mihail Venkov in the second period further enhanced Villa's position in the tie.
Litex's Brazilian-influenced midfield dictated the opening period, however, and they might have added to Bulgaria international Ivelin Popov's curling free-kick which opened the scoring in the 10th minute. The goal came after Reo-Coker was adjudged to have bundled over Sandrinho on the right-hand edge of the Aston Villa area.
The hosts totally controlled the opening exchanges, with the dangerous Tom a constant menace from the right.
Villa began upping the level of their performance and it was their own Bulgarian, Stiliyan Petrov, who began to disrupt the home attacks with regularity.
From one such breakdown, Villa launched a counter from which they thought they had levelled. Petrov put lone striker Gabriel Agbonlahor away down the left flank and when James Milner joined in, to cut back on to his right foot, he found Barry with his centre only for the goal to be ruled out for offside.
The game swung just before half-time, however, when Reo-Coker capitalised on Golubovic's error – and some defensive uncertainty – to sidefoot the ball into an empty net.
Centre-back Cambon's heavy challenge was punished with a 63rd-minute card and five minutes later another one reduced Litex to 10 men after he had been exposed by Agbonlahor's pace.
Litex had a second player dismissed when full-back Venkov punched the ball off the line. Barry's aim was true from 12 yards and Villa were ahead.
Villa scored again when a flowing move put Petrov in on goal in injury time. Although Golubovic saved his first shot, Petrov then rolled the ball in.
Litex Lovech (4-5-1): Golubovic; Cambon, Venkov, Nikolov, Berberovic; Manolev (Acedo, 75), Popov, Tom (Angelov, 85), Dudu (Barthe, 62), Niflore; Sandrinho. Substitutes not used: Todorov, Dos Santos, Bibishkov, Tsvetanov.
Aston Villa (4-5-1): Friedel; Luke Young, Cuellar, Laursen, Shorey; Gardner (Harewood, 68), Barry (Salifou, 78), Reo-Coker (Routledge, 74), Petrov, Milner; Agbonlahor. Substitutes not used: Guzan, Knight, Osbourne, Delfouneso.
Referee: C Zografos (Greece).