Defender Pareja joins Spartak

"It is a step forward in my career, because I am going to a league that is growing and to a top club playing the Champions League next season. It is a challenge," the 26-year-old international defender told reporters in Spain.

"I feel great sadness for all that I leave here: family, friends and a team that I doubt is like any other. All employees of the club have treated me wonderfully. I spent two incredible years here."

No financial details of the deal were disclosed.

Pareja started his career with homeland club Argentinos Juniors before joining Belgium giant Anderlecht, where he won the national title, Belgian Cup and Belgian Supercup.

In 2008 he won an Olympic gold medal in Beijing with the Argentina squad before joining Espanyol, for whom he played 58 matches and scored three goals.