Sam Allardyce's side looked to be slipping out of the competition on the away-goals rule following an outstanding 51st-minute strike from Georgi Iliev. However, with just 12 minutes remaining, a farcical own goal from Alexander Tunchev put Bolton on course for victory, and their safe passage was ensured in the 86th minute by substitute Kevin Nolan's third goal of the season.
Allardyce gambled by making seven changes to the side which defeated Portsmouth 1-0 at home last Saturday, and it only just paid off here in the Naftex Stadium, more than 200 miles from Plovdiv where Lokomotiv's ground failed to meet Uefa standards.
Allardyce was without four crucial players, with Ivan Campo, Nicky Hunt and Radhi Jaidi all injured, along with Gary Speed. He was forced to include 17-year-old Academy centre-back Jaraslaw Fojut in the squad, with the Polish youngster taking the nationality tally to 14 in the 18-man party.
But Allardyce still had enough confidence in his squad, with Mexico striker Jared Borgetti, French midfielder Fabrice Fernandes and Republic of Ireland Under-21 international Joey O'Brien handed their first starts. Allardyce also gave a debut to goalkeeper Ian Walker following his summer move from Leicester, and the former England international was relatively untroubled throughout the 90 minutes.
Certainly for the opening 50 minutes, the much-changed line-up appeared comfortable, adopting a professional, workmanlike attitude. Bolton were resolute, with fit-again Abdoulaye Faye slotting into the middle alongside Bruno N'Gotty, with Tal Ben Haim switched to right-back to cover the absence of Hunt.
Lokomotiv created little of note until the closing stages of the first half when they looked at their most dangerous. Bolton were devoid of invention in attack as they failed to break down the Lokomotiv rearguard, with just the one effort in the opening 45 minutes - a long-range, off-target effort from El Hadji Diouf.
Six minutes after the restart, Lokomotiv were in front in the most dramatic of circumstances - Iliev was 25 yards from goal when he let fly and the ball curled away from Walker into the top left-hand corner of the net.
With Bolton needing to chase the game, Allardyce made a double substitution in the 56th minute, with Nolan and Kevin Davies on for Fernandes and Borgetti. In the 78th minute, Bolton registered their first strike on target, with another sub - Hidetoshi Nakata - firing in a 25-yard free-kick which was comfortably scooped up after Davies had been brought down by Tunchev.
Within a minute, Bolton equalised in the most fortuitous of circumstances as Tunchev deflected Henrik Pedersen's left-wing cross beyond the advancing Stoyan Kolev. A few minutes later, the recovery was complete, with Davies teeing up Nolan to sidefoot home a sweet strike to send Bolton into the group stages.
Lokomotiv Plovdiv: Stoyan Kolev; Ivanov, Tunchev, Georgi Iliev, Kotev, Vandev, Krasimir Dimitrov, Krizmanic, Jancevski, Djordani, Robert Petrov. Substitutes: Martin Kamburov, Halimi, Stoinev, Dimitar Iliev, Georgiev, Hristev, Zlatinov.
Bolton Wanderers: Walker; N'Gotty, Okocha, Fernandes, Borgetti, Giannakopoulos, O'Brien, Faye, Ben Haim, Diouf, Pedersen. Substitutes: Jaaskelainen, Nolan, Gardner, Davies, Nakata, Vaz Te, Fojut.
Referee: Jouni Hyytia (Finland).Reuse content