Unai Emery does not expect Laurent Koscielny's latest fitness setback to be a major issue but knows Arsenal must use their captain wisely.

Koscielny pulled up during the warm-up before the Gunners' 3-0 win at Blackpool in the third round of the FA Cup, suffering from an apparent back complaint.

The former France centre-back missed his country's World Cup triumph due to a ruptured Achilles tendon sustained during Arsenal's Europa League semi-final loss to Atletico Madrid in May and only returned to action this month.

A patched-up backline kept Blackpool out at Bloomfield Road – not always in convincing fashion – and, with Shkodran Mustafi, Hector Bellerin and Nacho Monreal also joining Rob Holding among the walking wounded, Emery believes it would be easy to push Koscielny too hard, too soon.

"With Laurent we need to be calm with some moments in the training sessions because we are pushing him to play a lot of matches after his big injury," the Gunners boss told BBC Match of the Day.

"So maybe he needs some time not playing, but we had another player with big commitment to play in a different position today, Stephan Lichtsteiner.

"Laurent said he could not play the match but now we have one week to rest before the next game [away to West Ham in the Premier League] and hopefully he will be okay."

Teenage midfielder Joe Willock took his chance to shine, netting a first-half brace before Alex Iwobi completed the scoring eight minutes from time.

Willock's fellow 19-year-old Eddie Nketiah passed up three first-half opportunities in front of goal but Emery was satisfied with the striker's overall contribution.

"I am very proud of Willock and Eddie because Eddie had three good chances to score and Willock scored two," he added.

"They train very well in the second team and with us in training as well."

Replays showed Iwobi to be fractionally offside when he scored Arsenal's third and the winger was not penalised for possible handball in the build up to Willock's second.

Nevertheless, Blackpool manager Terry McPhillips did not want to dwell upon those incidents after his players acquitted themselves impressively.

"I think they know they've been in a game," he told BT Sport, having also overseen a 2-1 EFL Cup loss at Emirates Stadium this season.

"The last goal was offside but, in two games home and away against Arsenal, we've given it a real good go.

"I'm really proud of the lads. I've not seen the second goal – our footage isn't good enough. I'll see when I get home but my mate has text me about it."