The match was played over two days, as rain and nightfall forced the encounter to be suspended on Wednesday while the Italian, world No. 133, was trailing 5-6 in the third set and on serve, reports Efe.
When the match was resumed, Fabbiano held serve and managed to clinch the third set tie-break, earning his first career win over Wawrinka, who struggled to regain form.
The three-time Grand champion Wawrinka, currently world No. 224, missed the later part of the last season due to a knee injury that required surgery.
Next up for Fabbiano, who had reached the 2017 US Open third round, will be Stefano Tsitsipas of Greece, who defeated United States' Jared Donaldson 6-3, 6-2, 3-6, 4-6, 6-3.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
