Liverpool boss Jurgen Klopp believes the return of Alexis Sanchez gives Arsenal a timely boost ahead of their Sunday clash.

"Arsenal are an outstanding and strong side and they will have (Alexis) Sanchez back on the pitch for the first time this season," said Klopp.

"He gives that team another boost and that is of course an advantage to Arsenal.

"It's always difficult and will stay difficult. It's Arsenal. They have experience, they have speed and they have quality.

"They have technical skills and have the players that allow them to play lots of different systems.

"It has never been easy for Liverpool, probably in the past 20 years, against Arsenal, and it hasn't been easy for me since I've been here."