McClaren watched a large part of the 0-0 draw which secured Boro's place in the group stage of the tournament among a crowd of 5,013 after the fourth official could not find his name on the list of accredited representatives and repeatedly waved him away.
Despite that, McClaren left happy with the way his players bounced back from Sunday's 2-0 derby defeat by Sunderland to ensure their continued presence in Europe. "I'm delighted," he said. "It was vitally important to this club, not probably in terms of finance but in terms of profile and to give something to the fans."
Having arrived in Greece holding a 2-0 first leg lead, Boro knew a clean sheet would be enough for them to progress, but after a flurry of activity in the opening 26 minutes during which Luciano forced a save from goalkeeper Brad Jones and Gareth Southgate blocked a Levan Maghradze effort, they had little trouble keeping the home side out.
There were 87 minutes on the clock when substitute Szilard Nemeth cleared former Teessider Emerson's header off the line, although had Massimo Maccarone's 33rd-minute strike been allowed to stand - a harsh offside decision saw it chalked off - the visitors would have left with a second win.
"We should have scored tonight - we had chances to," McClaren said. "It was a good performance away in Europe, one which was typical of us last season."
Xanthi: Pizanowsk; Papadimitriou, Torossidis (Kazakis, 47), Sikov, Paviot, Antzas, Maghradze (Garpozis, 68), Luciano, Labriakos, Emerson, Gomes Andrade (Leo Mineiro, 60). Substitutes not used: Anastasopoulos, Zapropoulos, Carabas, Lafata.
Middlesbrough: Jones; Xavier, Southgate, Riggott, Pogatetz, Queudrue (Parnaby, 78), Doriva, Boateng, Morrison, Maccarone (Nemeth, 71), Hasselbaink (Yakubu, 71). Substitutes not used: Knight, Bates, Mendieta, Johnson.
Referee: K Kircher (Germany)
* In last night's other Uefa Cup first-round ties involving British and Irish clubs, Hibernian crashed out after losing 5-1 in Ukraine against Dnipro, after a goalless draw at Easter Road in the first leg. Cork were beaten 2-1 at home by Slavia Prague, and went out 4-1 on aggregate.
- More about: