Second seed Andreas Seppi secured his place in the quarterfinals with a win over Igor Sijsling of the Netherlands at the Kremlin Cup on Thursday.
Italy's Seppi was a break down to Sijsling at one stage in the first set before coming back to win, while Sijsling faded slightly in the second as Seppi wrapped up a 7-5, 6-2 win.
The match was Seppi's first of the tournament after he received a first-round bye.
"It was a tough first set, I was a break down, didn't have so good start. It's always tough, the first match of the tournament, to get a little bit in the rhythm," Seppi told R-Sport.
"After the first set I played much more aggressive, tried to go a little bit more to the net and I served pretty well."
Seppi now faces Japan's Tatsuma Ito, the eighth seed, who beat Russian qualifier Konstantin Kravchuk 7-6 (7), 2-6, 6-3 on Monday.
The two have never played before, but world No. 25 Seppi said he was impressed by the 63rd-ranked Ito.
"I saw him playing yesterday a little bit and he's a pretty solid player, especially from the baseline, he has a lot of rallies, so I think again it's going to be a difficult match for me," Seppi said.
The winner is assured of a semifinal against an unseeded player after sixth seed Denis Istomin and reigining champion Viktor Troicki crashed out of that section of the draw.