Martin O’Neill stunned after one of his worst nights at Celtic

Celtic manager Martin O’Neill admitted Tuesday’s defeat to LASK ranked as one of his most painful nights at the club as their Champions League hopes went up in smoke during a disastrous second leg in Austria.

Callum McGregor put his team 4-0 up on aggregate in the play-off when he struck from 18 yards in the 21st minute, but they went on to lose 5-1 on the night after extra-time (5-4 on aggregate).

Defeat sends Celtic into the Europa League and delivers a damaging financial blow that will cost the club at least £20m.

“I would say absolutely, yes,” O’Neill said when asked if it was one of his worst experiences in the dugout.

“I’d put it down before the disappointment of losing the UEFA Cup final in 2003, but it’s so, so disappointing.

“We should have been out of sight by half-time. We scored a goal, which was great, we missed two great, great opportunities. And then we give them a lifeline just before half-time and then one just after it. And they come roaring back.

“And obviously we conceded, from our viewpoint, not good goals at all. But that’s my team and that’s my responsibility.

“I’m disappointed that we’ve conceded the goals in the manner which we did.”

When asked whether his squad was strong enough, O’Neill said: “These are tough games. And it might only be a Champions League qualifying game, but it felt like a Champions League game. I thought they were a fine side.

“But that doesn’t matter. We should have been able to have seen it through. And we didn’t do. Talking about the squad, that’s for another day.”