Alexis Sanchez has developed into a "special" all-round forward while at Arsenal, according to boss Arsene Wenger.

Chile star Sanchez netted his 26th goal in all competitions this season in the 4-1 rout of Stoke City on Saturday, while his exquisite pass for Mesut Ozil to score established him as the only player to have double figures in the Premier League for goals and assists this term.

The 27-year-old's future beyond the end of the campaign remains in doubt, even though Wenger remains confident he will sign an extension to a deal that expires in 2018.

Sanchez has been linked with a move to Manchester City, among other clubs, and his manager believes one of the hottest properties in Europe is a more complete player than when he moved to Emirates Stadium from Barcelona in 2014.

"I think overall at the start he was, as a player, mainly focused on scoring goals and he developed his assist potential with us very well," Wenger said.

"He plays now in a position where he can provide as well as score. I believe he has become a complete player and developed very well here at Arsenal.

"It's an exceptional achievement to score and provide in double figures. That is to be a special player."

Sanchez faces a late fitness test ahead of Tuesday's match at home to relegated Sunderland, although Wenger praised his determination to overcome a blow to his thigh.

"He will have a test," the Frenchman said. "Yesterday [Sunday] he didn't look too good but, with him, you never know.

"It was just a kick on his thigh so it is possible he will be available."

Elsewhere on the injury front for Arsenal, centre-back Laurent Koscielny is doubtful due to a recurrence of the calf problem that ruled him out of last week's 2-0 win at Southampton, while Alex Oxlade-Chamberlain will be unable to assist his team-mates in their bid for a top four spot.

The England midfielder sustained a hamstring injury at St Mary's and will sit out Sunderland and Everton's visits to North London this week, although Wenger rates him positively as a "80-20" chance to feature in the FA Cup final against Chelsea on May 27.