No.3 seed Sergiy prevailed over world no.295 Calvin Hemery 7-6 (4), 4-6, 6-2 to move into the Open BNP Paribas Banque de Bretagne Quimper challenger second round on Tuesday.
The players traded breaks twice in the opening set. Sergiy won a tie-breaker 7-4 to gain advantage.
Games went with serve until the seventh game of the second set, when the 22-year-old French qualifier made a break and held to force a decider.
A break in the fourth game was enough for Stako to seal the win after one hour and 55 minutes of play.
Stats: aces (6-7), double faults (2-3), total points won (92-88).
For a place in the quarter-finals, Sergiy faces Enrique...
Sergiy suffered a 4-6, 7-6 (2), 6-7 (4) defeat to world no.193 Blaz Kavcic in Open de Rennes second round action on Thursday.
The fourth seed came back from being a set and a break behind to force a decider. Unfortunately, his rival had stronger finish in the third set tie-break and managed to win this highly competitive contest in two hours and 40 minutes.
Stats: aces (13-15), double faults (2-1), total points won (110-123).
Sergiy and his doubles partner Roman Jebavy play against Sanchai and Sonchat Ratiwatana of Thailand in quarter-final clash later today.
No.4 seed Sergiy reached the second round of the Open de Rennes challenger on Wednesday with a 6-3, 5-7, 6-2 victory over world no.411 Remi Boutillier in one hour and 40 minutes.
Stako broke in the fourth game of the first set to move ahead, but the French qualifier responded by breaking in the 12th game of the second set to level the contest.
The Kiev native, who is currently ranked no.111st in the ATP rankings, regained the momentum in the decider, and with two breaks of serve - in the first and third games - sealed the win.
Stats: aces (6-3), double faults (5-0), total points won (93-80).
Sergiy will next face either Blaz Kavcic (SLO) or Jurgen...