Heimir Hallgrimsson conceded too many of his Republic of Ireland players were "off their game" after slipping to a 1-0 defeat against Kosovo in their Nations League opener. 

The Republic of Ireland looked set to begin their Group B3 campaign with a point, only for Kosovo captain Vedat Muriqi to score an 83rd-minute winner for his side. 

It brought an end to Hallgrimsson's eight-game unbeaten run in all competitions, suffering their first defeat since October last year when they were beaten 1-0 by Portugal. 

No team has failed to score in more Nations League games than the Republic of Ireland (15 – level with San Marino and Andorra), and Hallgrimsson admitted his team were second best at Stadiumi Fadil Vokrri. 

Kosovo finished with an expected goals (xG) total of 2.74 from their 22 shots compared to the Republic of Ireland's measly 0.25 from their three attempts at Arijanet Muric. 

Hallgrimsson was unable to identify why his team struggled to get a foothold in the match, but he said some of his players must improve as the international break goes on. 

"They were just better than us on the day," Hallgrimsson said. "We had too many players who were off their game.

"I wish I knew [why Ireland were so passive]. I would have changed that in the game. We wanted to be safe, we wanted to be compact and keep a clean sheet first and foremost."

It could have been an even more convincing scoreline for Kosovo had it not been for Caoimhin Kelleher, who made five important saves throughout the match. 

Kelleher has only made more saves in a Nations League game against England in September 2024 (seven), showcasing Kosovo's dominance. 

Kosovo have now won seven of their last eight Nations League games (L1), including each of the last four in a row – their outright longest winning run in the competition.

The Republic of Ireland face Israel home and away, either side of facing Austria at home, though Hallgrimsson believes Kosovo will stand a good chance of topping the group. 

"I would say Kosovo has a strong chance of winning this group," he added. "Austria is the favourites, the highest in the FIFA ranking. Beforehand, they are seen as the favourites."

The only positive for Hallgrimsson was that none of his players picked up any injuries, and he does not expect any of his players to pull out of their remaining three matches. 

"The overall assessment is I'm very disappointed with the performance," Hallgrimsson said. 

"We could have survived with a draw but the performance was below what we expected. Individually a lot of players had an off day and collectively we were lacking initiative."