Costa Rican forward Joel Campbell has admitted that he has found it difficult to make the transition from Arsenal to Villarreal in the middle of the season.

The 22-year-old joined Villarreal on loan from Arsenal in January, but has largely struggled to make an impact with the Spanish club.

However, the attacker has insisted that he will continue "working very hard" in a bid to contribute in the final months of the campaign.

"To join a team in the middle of the season is never easy, especially when you haven't played much previously," Campbell is quoted as telling reporters in Spain.

"The truth is that I'm working very hard now to get my opportunities and be at my best when I get them."

Campbell spent last season on loan at Olympiacos.