Kozlov needed a bit more time to take out 17-year-old Daniel Masur of Germany 5-7, 6-2, 6-1. The 14-year-old qualifier was up 5-2 in the first set, had two set points with Masur serving at 3-5, but couldn't close out the first set against the world's 19th-ranked junior.
"The first couple of games were pretty rough, I was kind of nervous," said Kozlov, the youngest player in the draw by more than a year. "Not nervous where I couldn't play, but throughout the whole first set I was kind of nervous. I played well until 5-2, then kind of gave it up."
Kozlov, who says people have told him he plays like 19-year-old Australian Bernard Tomic, broke Masur to open the second set.
"It was tough," Kozlov said. "It's a good thing I broke the first game, because otherwise it would have been hard. But I just stopped thinking about it, and played like I wasn't going to lose."
In the third set, Kozlov again got an early break and coasted to the win. With his variety and his ability to change pace and direction when least expected, Kozlov thinks the surface is a good one for him.
"I feel pretty comfortable on it," said Kozlov, who qualified and won a round at the Roehampton Grade 1 last week. "My serve kind of joins the grass, and I feel very comfortable on it, let's put it that way."
Kozlov's father Andrei, who runs a tennis academy in Pembroke Pines, Florida, arrived at the All England Club from Florida this morning, but he didn't make the trip solely to see his son play his first match in the shadow of Wimbledon's Centre Court.
"He's coaching Camila Giorgi," Kozlov said of the 20-year-old Italian qualifier who lost in the fourth round to No. 3 seed Agnieszka Radwanska today. "He helps her out a lot and I usually hit with her a lot when I'm home."
No wonder Kozlov improves so quickly. He practices with a pretty good WTA pro when they're together.