Australian batting stalwart Usman Khawaja believes fellow opener David Warner is probably at his best as he prepares for the tough English summer, which includes the World Test Championship final against India and the Ashes.

Warner, 36, had endured a difficult tour of India earlier this year, and even though the Delhi Capitals skipper showed attacking intent while amassing 516 runs from 14 matches in the IPL, he will have his task cut out in the seaming English conditions.