Arsenal forward Theo Walcott has warned the Premier League that hat-trick hero Alexis Sanchez is only warming up following his heroics at Leicester City.

The Chilean ace, who scored 24 times last term, opened his account for this season in style as he fired three past the Foxes in Saturday's 5-2 win at the King Power Stadium.

The former Barcelona man had previously gone eight games without scoring, but Walcott, who cancelled out Jamie Vardy's opener yesterday, says that his teaammate is back to his red-hot best.

"Alexis is a top-quality player and even when he is not scoring goals he works so hard for us. He tracks back and does a lot for the team," he told Arsenal's official website.

"I am sure he going to flourish now with many, many more important goals. It had been a long time coming, he knew that himself. But he is very pleased now."

Olivier Giroud added a fifth late on as the Gunners bounced back from a 2-0 defeat at Chelsea last weekend.