A controversial penalty in the dying minutes denied Celtic of all three points in their Europa League group clash against Udinese at Parkhead.

Referee Bulent Yildirim judged that home striker Gary Hooper had brought down Neuton in the 86th minute and Almen Abdi levelled from the spot.

Celtic manager Neil Lennon later described the decision as "shocking" but praised his players for their effort, saying: "I couldn't have asked for any more."

Earlier, Hooper earned Celtic a first half-penalty when he was fouled by Joel Ekstrand and Ki Sung-yueng converted to give the home team a deserved edge.

Lennon had made four changes to his reshuffled Celtic side for the match. Keeper Fraser Forster was surprisingly replaced by Lukasz Zaluska, while defender Glenn Loovens and striker Anthony Stokes were also dropped.

With left-back Badr El-Kaddouri also cup-tied, in came Charlie Mulgrew, Victor Wanyama and Mohamed Bangura, who was making his first start.

Udinese were without veteran star Antonio Di Natale, who was allowed to rest back in Italy. Coach Francesco Guidolin was questioned for his decision not to bring any of his other recognised first-team strikers to Glasgow and he was looking for goals from Diego Fabbrini and midfielder Almen Abdi.

Celtic had lost only once at home before to Italian opposition over 90 minutes which gave the home fans some encouragement, although live television and the early kick-off had clearly affected the attendance, with Parkhead less than half-full at kick-off.

Lennon had warned his side against losing another early goal in Europe. However, it was the Hoops who took the lead after winning a penalty with less than two minutes played when striker Gary Hooper was pulled down by Udinese defender Lars Joel Ekstrand.

Referee Yildirim did not point to the spot at first but after appearing to wait for some guidance from his linesman officials he eventually confirmed what had looked obvious.

After some delay midfielder Ki Sung-yueng slammed the penalty high past captain and keeper Samir Handanovic.

The Italian side were clearly rattled and could not get a foothold in the game as Celtic grew in confidence.

In the 22nd minute Zaluska pushed a long-range shot from midfielder Emmanuel Badu round the post but the visitors could not capitalise on the corner,

Moments later Celtic's stand-in skipper Beram Kayal was booked for a foul on Badu.

Just before the half-hour Zaluska made a comfortable save from Abdi's drive but seconds later Hooper forced Handanovic into an even better stop at the other end with a powerful drive from the edge of the box after being set up by James Forrest.

In the 37th minute the lively Bangura was fouled by Udinese midfielder Thierry Doubai 30 yards from goal but Ki flashed the free-kick wide.

The South Korea international midfielder scored from the spot in the third minutes after striker Gary Hooper had been .

Both sides were under strength but a determined Celtic side bossed the rest of the first 45 minutes against the side joint top of Serie A, although there were no more clear-cut chances at either end.

Right-back Mark Wilson replaced Joe Ledley at the interval with Adam Matthews moving to the other side of the park while, for the visitors, Mauricio Isla and Medhi Benatia came on for Roberto Pereyra and Dusan Basta.

In the 51st minute Badu was booked for illegally halting Forrest's progress as he drove at the Udinese defence and from the resultant free-kick, Mulgrew's curled shot was heading for the top corner until Handanovic flew to his right-hand side to parry clear.

That near-miss inspired the home fans to crank up the atmosphere which was better than the game deserved.

Celtic looked in no real danger of losing their lead although a few crosses in to their box, as the Italian side tried to battle back, had the fans holding their breath.

In the 62nd minute Wanyama fouled Fabbrini 30 yards from goal and from Cristian Battocchio's chipped free-kick, Abdi had a shot which ended at the feet of Benatia who slipped the ball in to the net from close range.

However, after another delay and some confusion as to why, referee Yildirim awarded Celtic a free-kick inside the box.

Forrest was replaced by Georgios Samaras in the 71st minute and as the game opened up Celtic went looking for the goal which would surely guarantee the three points.

Abdi drove just wide from distance in the 84th minute and moments later, after Samaras led a Celtic counter-attack, Ki's thunderbolt drive was tipped over the bar by Handanovic.

At the other end Zaluska made a fine save from Isla, who only had the keeper to beat. Hooper conceded a penalty in the 86th minute for a foul on Neuton and Abdi sent Zaluska the wrong way from the spot.

In the first minute of injury time, after Benatia fouled Samaras 25 yards out, Mulgrew forced another great save from Handanovic with a powerful free-kick.

The match ended with the Celtic players still protesting over the penalty at the final whistle.