FC Barcelona head coach Hansi Flick confirmed on Tuesday that Wojciech Szczesny has become his first-choice goalkeeper ahead of Inaki Pena.

Former Arsenal, Roma and Juventus keeper Szczesny joined Barcelona in October, coming out of retirement after Marc-Andre ter Stegen sustained a season-ending knee injury. However, fitness concerns and Pena's good form initially delayed Szczesny's debut until Jan. 4, when he featured in Barca's 4-0 Copa del Rey victory over fourth-tier Barbastro.

He then played in both matches as Barcelona claimed the Spanish Supercup - though he was sent off in the final with around half an hour remaining.

Although Pena returned in goal for Barca's 2-0 Copa del Rey win at home to Betis and a 1-1 LaLiga draw at Getafe, Szczesny was chosen for the Champions League clash away to Benfica, which ended 5-4 in Barca's favor. Despite conceding a penalty and being at fault in Benfica's second goal, Flick kept Szczesny in the side for the subsequent 7-1 thrashing of Valencia.

Asked about his decision for Barca's final Champions League group-stage match at home to Atalanta, Flick made it clear that Szczesny is now his primary choice in goal.

"It is one of the most difficult decisions I have had to make. It's always difficult because the goalkeeper is always very special," he said.

Flick insisted this does not reflect a lack of trust in Pena.

"I know that when I say something nice about Tek (Szczesny), it seems as if Inaki is losing out, I don't like that. I have to choose the goalkeeper and they are both great goalkeepers.

"We have inclined towards Tek for tomorrow (Wednesday). I always look for the best for my team and that is how I see it at the moment, although Inaki has done very well," he added.

Flick also highlighted that Szczesny's recent experience in Italy gives him useful insight into Atalanta, which could serve as another advantage.

Barcelona suffered an additional injury setback on Tuesday with the news that Danish defender Andreas Christensen, who was close to returning from an Achilles tendon injury, will be out for another three weeks due to a right calf problem. With Inigo Martinez still sidelined by a hamstring issue, Eric Garcia, Pau Cubarsi and Ronald Araujo remain the club's only fit central defenders.