The left-arm fast bowler's first 'five-for' for Essex in just his second Championship match was instrumental in Yorkshire being skittled out for a meagre 113.

Essex ended the first day on 188 for five, a lead of 75 runs, with captain Ryan ten Doeschate 61 not out.

Amir, speaking after joining Essex following his Champions Trophy campaign, insisted in June that he had no problems with his new team-mate.

"I met him the first day when I arrived and he was very nice," said Amir of Cook.

"No (there are no issues between us), nothing. He's always nice and always very supportive."