First Celtic goals for debutant Gary Hooper and Efrain Juarez earned Lennon's men a 2-1 win but Paulo Cesar's first-half away goal had left them needing five to progress. While the Portuguese side now look forward to the Champions League play-offs, Celtic will have to negotiate their way through the same stages of the Europa League.

Lennon said: "Overall I'm delighted with the performance and intensity and all the things you ask for - commitment and passion.

"The pace we played at and the passing was very pleasing.

"At half-time we just asked them to win the game and I thought we deserved to win.

"But we keep conceding soft goals. I'm learning from it and hopefully the players are learning."

Cesar ran across Cha Du-ri before heading home as Celtic lost their ninth goal in four games, including the Emirates Cup.

Lennon added: "I just think it was a poor goal, the guy has got across Cha. I didn't think there was much pace on the cross and he headed it from far out."

But he went on: "I thought we were excellent in the second half.

"There were some great performances."

Lennon has not heard anything from Aiden McGeady, who is due back in Glasgow tomorrow following talks with Spartak Moscow.

And he refused to dampen speculation over the potential re-signing of Manchester City's Craig Bellamy, who spent several months on loan at Parkhead in 2005.

"I wouldn't like to say anything at the moment," the Celtic manager responded when asked about reports of a move.

When asked whether the club were in a position to pull off that sort of transfer, he replied: "I would hope so but I don't know. It's still up in the air regards that."