Mikel Arteta admitted Arsenal were suffering from "fatigue" after an own goal from Shakhtar Donetsk keeper Dmytro Riznyk gave the Gunners a 1-0 win in the Champions League on Tuesday. Arteta`s side crashed to a damaging 2-0 defeat against the Cherries in the Premier League last weekend. That was Arsenal`s first loss in all competitions since the Champions League quarter-final second leg at Bayern Munich in April. Their response against Shakhtar was unconvincing, but they did enough to claim three points thanks to Riznyk`s first half own goal from Gabriel Martinelli`s strike. Leandro Trossard missed a late Arsenal penalty that would have put a flattering gloss on the scoreline at the Emirates Stadium. 

"It`s always difficult in Champions League. We should have scored more in first half and the second half I felt a bit of fatigue," Arteta said. "Credit to Shakhtar, they are brave. When you give them time on the ball and you lose the ball you will suffer. "Playing 60 minutes with 10 men a few days ago is difficult. We left the game a bit open but we dug in for three points." Frustrated that Trossard took the penalty instead of Kai Havertz, Arteta added: "I don`t know. He is one of the takers but Leo took it." Worryingly for Arteta, Riccardo Calafiori was forced off in the second half after appearing to injury his knee in the latest injury blow for a team currently missing Bukayo Saka, Martin Odegaard and Jurrien Timber. Arteta is already without suspended French defender William Saliba for Sunday`s crucial Premier League clash with leaders Liverpool.