LONDON - Arsenal needed an own goal to seal a scrappy 1-0 win over Shakhtar Donetsk on Tuesday as they made it two wins out of three in the Champions League to soften the blow of their first domestic league defeat of the season at the weekend.

The hosts missed a penalty in the second half and squandered a number of decent chances, but the reality was they never found top gear and had to withstand some late pressure from their Ukrainian opponents.

Arsenal, who were beaten 2-0 by Bournemouth in the Premier League on Saturday, made a fast start with Brazilians Gabriel Martinelli and Gabriel Jesus both having good opportunities before a fortunate opener in the 29th minute.

A low shot from Martinelli rebounded off the post and off the back of Shakhtar keeper Dmytro Riznyk for what turned out to be the only goal of the game.

Arsenal would have doubled their advantage before halftime were it not for Shakhtar captain Mykola Matviyenko who hooked the ball off the line to prevent a diving Kai Havertz nodding in.

Leandro Trossard also missed a second-half penalty awarded by VAR following a handball in the box.

"We had four big, big chances (in the first half). We should have converted them and put the game to bed," Arsenal manager Mikel Arteta told reporters after the game.

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The second half was difficult he added. "We looked tired and lacked sharpness with and without the ball."

Shakhtar, who are yet to win in the Champions League this season, put more pressure on Arsenal after the interval and went close to equalizing when substitute Pedrinho had a long-range effort superbly saved by Arsenal keeper David Raya in stoppage time.

"I think we deserved an equalizer" Shakhtar coach Marino Pusic told reporters. "We were chasing for an equalizer till the end of the game... we did our best".

Victory lifts Arsenal provisionally into the top four of the new 36-team league phase before Wednesday's fixtures with their next match away at Inter Milan. Shakhtar will seek to bounce back in their next match at home to Swiss side Young Boys.

Arsenal will be relieved to have sealed the win but without key playmakers Bukayo Saka and captain Martin Odegaard who were missing through injury, were well off their fluent best.

Arteta, whose side have also suffered from three domestic league red cards this season, substituted defender Ben White at halftime after he had picked up a yellow card.

Riccardo Calafiori was also taken off with 20 minutes to go after the Italian landed awkwardly following a challenge.

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"He (Calafiori) felt something. I don’t know the extent of that so in that sense not great news," Arteta said.