It was a key consider her cost to the Cincinnati Open title earlier this month.
Evaluation from that event confirmed how Gauff is hitting nearer to the road however nonetheless sustaining her serve pace – underlining a major enchancment in her accuracy.
Gauff now has full confidence her serve could be too sizzling for opponents to deal with – and it confirmed instantly in opposition to Sonmez.
The opening recreation noticed Gauff thump a 112mph ace down the center, adopted by an unreturned first serve and one other ace, on her method to holding serve in lower than 90 seconds.
Sonmez struggled to get balls into play each time Gauff landed a primary serve within the first set, with the world quantity 4 profitable 93% of these factors.
Gauff broke once more for a 1-0 lead within the second set, however her serve was not as efficient as Sonmez levelled at 2-2 and held three extra break factors for a 4-2 lead.
However a exact ace out extensive and a 115mph unreturned first serve enabled Gauff to cling on in a recreation which you felt she would have misplaced a yr in the past.
The gutsy maintain laid the platform for Gauff to instantly break for 4-3 earlier than securing victory with one other service recreation which displayed her perception.
Gauff hit a trio of unreturned first serves – all just below the 120mph mark, teeing up three match factors as Sonmez buckled on the primary after a brief rally.
“Psychologically, I am now going to go for the ace, or I do know I can hit the serve and the return might be not going to come back again,” mentioned Gauff, who will play Spain’s Paula Badosa or Australia’s Daria Kastakina within the second spherical.
“Final yr I actually was like I hope I make it in. It is such a giant distinction realizing virtually each serve I am making an attempt to principally hit 110, 115, 120mph if I can.”
