Rising star Borna Coric was defeated in the first round of the Miami Open on Thursday after he was beaten 6-4, 5-7, 5-7 by Denis Istomin.
Coric, who is ranked 46th in the world, broke serve in the fifth game to take a 3-2 lead before Istomin returned the favour to bring himself level at 3-3. However, Coric broke Istomin once more en route to clinching the first set.
The 19-year-old found himself trailing 3-0 early on in the second set, but despite recovering to make it 5-5, he was unable to stop the 29-year-old from winning the second set.
The third set was much the same story as Coric was in contention until he slipped up in the 12th game, when he was broken by Istomin.
Meanwhile, Japanese qualifier Tatsuma Ito booked his spot in the second round following a 7-6 (3), 6-2 win over Nicolas Mahut.
Ito emerged victorious in a tie-break in the first set before dominanting Mahut in the second set, when he broke serve on three occasions to advance to the second round, where he will face 16th seed Gael Monfils. The Frenchman was given a bye in the first round.
Meanwhile, Marcos Baghdatis, Denis Kudla, Andreas Seppi and Federico Delbonis also progressed to the second round.