Arsenal defender Laurent Koscielny has praised teammate Alexis Sanchez after the striker scored twice during Saturday's win over Stoke City.

The Chile international took his tally to 18 goals for the season as the Gunners saw off the Potters 3-0 to boost their hopes of Champions League qualification.

Despite a hectic schedule in the Premier League, Koscielny believes that Sanchez should be given credit for both his prowess in front of goal and his fitness.

"Alexis is amazing because he's played more than 25 games and he still runs like it's his first game," the Frenchman told the club's official website.

"It's amazing and it's not just in attack - he defends well. If he needs to run back to help us defend, he does, so he has a good mentality, which makes him a world-class player."

Arsenal return to Premier League action on Sunday when they face champions Manchester City at the Etihad Stadium.