GLASGOW (AFP) Celtic manager Neil Lennon hopes that adding experience to his stuttering side will salvage their European campaign after crashing out of the Champions League to Sporting Braga at the first hurdle. A 2-1 home second leg win on Wednesday night was not enough for Celtic as they exited 4-2 on aggregate to the Portuguese league runners-up in their third round qualifying tie. The result means Celtic will now have to negotiate a play-off for a place in the Europa League, losing out on the much needed Champions League cash to Old Firm rivals Rangers for the second year running. The Glasgow side have failed to keep a clean sheet during a dismal pre-season, conceding 15 goals in eight games, and manager Lennon admits he is worried about his sides defensive frailties. When asked if he would be happy going into the Scottish Premier League season and Europa League campaign with his current back four he said: Obviously I wouldnt be if they were struggling to keep clean sheets but if I have to then I will. We keep conceding poor goals. Im learning from it and hopefully a few of the players are too. I would like to keep a balanced back four as much as we can so they can build up some relationship between each other. We will think about that over the next couple of days and hopefully we will get one in or two if we can in the meantime. The club have brought in seven new signings in the summer transfer window but have missed out on a couple of high profile players, most notably Sol Campbell, England keeper David James and midfielder Jamie Bullard. And the Celtic boss believes it is players of their calibre that are needed to give some much needed experience to his squad. Looking at the squad there is still a bit of inexperience and thats why we went for Campbell and thats why we went for James and Bullard but we will keep going, Lennon added. At Parkhead on Wednesday Celtic had always faced an uphill battle after their 3-0 defeat in Portugal but the home sides task became even tougher when Paulo Cesar claimed a vital away goal as he headed Braga in to a 20th minute lead. Celtic looked flat in the first half but were vastly improved after the break and Gary Hooper restored some pride in the 51st minute when he netted on his competitive debut. Mexican midfielder Efrain Juarez briefly gave the home fans hope when he headed Celtic into the lead 12 minutes from time but it was too little too late. I dont think there was a lot between the two teams over the two games, Lennon insisted. To take a 3-0 deficit in to the home game was a big ask but it was doable. But we always knew we had to keep the door shut at the back and we gave ourselves a mountain to climb after that. We knew we were on a precipice with the away goal and you have to keep your concentration at the maximum at this level. I got them in at half-time and made a change and they were excellent in the second-half and you are thinking that if we hadnt conceded a goal then at 2-0 with ten or 15 minutes to go it would have been really interesting. I dont like losing and I dont like going out so overall I am very disappointed but there is still a lot of stuff I am pleased with tonight. The Celtic boss said he expected to meet with wantaway winger Aiden McGeady this week to find out his decision about a potential move to Spartak Moscow.