Alexei Popyrin has battled back from 4-2 down in the final set to beat Jordanian wildcard Abdullah Shelbayh and progress in the Qatar Open.
The Australian No.3 won 6-3 4-6 6-4 with the decisive moment in the two-hour match in Doha being a 20-point ninth game in the third set when he broke to set himself up to serve out, which he did to love.
The 20-year-old Shelbayh, ranked 230 in the world proved an unexpected handful for world No.46 Popyrin but the work--out should set him up for stiffer challenges.
Popyrin next plays the winner of Tuesday's (Wednesday AEDT) match between eighth-seed Tallon Griekspoor and qualifier Hugo Grenier with fourth-seed Alexander Bublik his potential last-eight opponent.
Elsewhere No.7 seed Lorenzo Musetti was upset by Zhizhen Zhang 6-2 6-0 and Marton Fucsovics beat veteran Roberto Bautista Agut 6-1 6-3 while Pavel Kotov and Fabian Marozsan also progressed.