Seventh seed John Millman booked his spot in the second round of the Memphis Open following a hard-fought 6-3, 6-7 (3) 7-5 win over Austin Krajicek.
Millman seemed to be cruising after clinching the first set, but Krajicek refused to go down without a fight and brought himself back into contention after claiming the second set via a tie-break.
However, Millman maintained his composure and managed to see off Krajicek in two hours and 42 minutes. He will now face Benjamin Becker in the second round after the German defeated Tommy Paul 6-4, 3-6, 6-3.
Marcel Granollers set up a last-16 clash with Donald Young after he defeated Malek Jaziri 6-1, 6-3.
Granollers broke his opponent in the very first game of the match and never looked back again. The first set took only 27 minutes.
The second stanza was a slightly closer affair as the Tunisian broke to lead 2-1. However, the Spaniard responded with two breaks of his own before serving out the set and the match with aplomb.
Granollers' duel with Young will be a fascinating one. The former was tipped for greatness in his youth after he became the youngest male to win a Junior Grand Slam event in 2005.
However, he has failed to live up to all the hype. At 26 years of age, the American is now hoping things will be different this year and if he is able to triumph over Granollers he will have a relatively clear run to the final where a potential meeting with Kei Nishikori looms.
Meawhile, eighth seed Damir Dzumhur, Henri Laaksonen, Ricardas Berankis and Taylor Fritz also advanced to the second round.