Day two at Dubai Tennis stadium saw Sinner, Hurkacz and Khachanov progress to the next round.
At the Dubai Duty Free Tennis Championships, fourth seeded Italian Jannik Sinner has beaten Spain's Alejandro Davidovich Fokina on centre court in three sets.
On court one, fifth seed Hubert Hurkacz won against Kazakhstan's Alexander Bublik 6-3 6-1.
In the day's early matches, American Mackenzie McDonald defeated seventh-seeded Russian Aslan Karatsev 7-5 6-3 on Centre Court.
Russia's Karen Khachanov beat Alex de Minaur from Australia on Court one 6-3 6-7 7-5.
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