Neil Lennon spoke of an “amazing” night after Olivier Ntcham’s last-gasp winner against Lazio took Celtic into the last 32 of the Europa League with two Group E fixtures remaining.

Ciro Immobile opened the scoring for the home side but the Celtic winger James Forrest deservedly equalised with a terrific finish. Then, in the fifth minute of added time at the end of a thrilling game, the midfielder Ntcham, on for Ryan Christie, finished a counter attack to secure the win.

It was Celtic’s first win in Italy in 13 attempts and kept them top of their section with a guarantee of European football after Christmas. The goal also clinched a double over the Serie A side.

Lennon said: “I am so happy and proud of the team. Not just winning the game but the way they played the game, the character, the bravery and above all else, real quality.

“It was a titanic game again, a brilliant game to watch and it was a game we thoroughly deserved to win. To come here and play as good as that; this team keeps setting new boundaries. We have qualified after four games. That is unheard of for Celtic in Europe.

“It is an amazing night, not just for me, the players, the board and obviously the magnificent support we had in the stadium tonight. It is historic. It is a privilege for me to coach these players and work with my backroom staff who do an unbelievable job behind the scenes.

“We are in a good place at the minute. It is job done as far as qualifying for the new year. We have a lot of work to do domestically but it is an amazing night for the team and the club.”

Celtic were pinned back early before conceding. When Manuel Lazzari curled in a cross from deep, the ball skipped off the head of Christopher Jullien and Immobile, unmarked, took no time in thrashing the ball past Fraser Forster.

Celtic had to come out of their shell and they did but in the 20th minute it took a timely tackle from Kris Ajer to thwart Immobile when he was left with only Forster to beat after skipping past Hatem Elhamed. Then, only a brilliant block by Ryan Christie prevented Immobile testing Forster with another effort.

Celtic went in at half-time level after Francesco Acerbi let Mohamed Elyounoussi’s pass slip under his foot and Forrest rifled in from an angle.

Forster saved a header from Sergej Milinkovic-Savic and then was bailed out when he flapped at the consequent corner, with Jullien clearing Felipe Caicedo’s effort off the line.

However, it was Lazio who appeared more grateful to hear the half-time whistle and looked no more composed after the interval as Celtic threatened to take the lead. Lazio sent on Luis Alberto and the club captain, Senad Lulic, for Jony and Lucas Leiva but there was little improvement.

There was a Lazio penalty claim in the 66th minute when Immobile’s drive appeared to be blocked by the arm of Jullien but the referee, Tobias Stieler, took no notice.

Play stretched further in the final stages. A corner from Luis Alberto rebounded off the post before the Celtic striker Odsonne Édouard failed to hit the target with a drive after a counterattack. Forster made decent saves from Valon Berisha and Alberto before Ntcham took a pass from Édouard and chipped the goalkeeper Thomas Strakosha for the most dramatic of endings.

Asked where it ranked in comparison to Celtic’s 2-1 Champions League win against Barcelona in 2012 at Parkhead in Lennon’s first stint as manager, he said: “It is just behind it. To beat Barcelona was a great night and a great achievement for the club but this is almost on a par, to come here and play a team who are in great form, packed with international stars.”

Simone Inzaghi, the Lazio manager, said: “There is still hope. Celtic have beaten us home and away, so maybe they will be able to beat Cluj in Romania and we have to win against Rennes and Cluj. We hit the post, their goalkeeper saved a lot and we also had the referee against us because at 1-1 there was a clear penalty for us that wasn’t given to us so it could have changed the game.”