Auckland, Jan. 14 -- Top seed Ben Shelton advanced to the quarterfinals of the ASB Classic on Wednesday here in New Zealand, after battling past Argentina's Francisco Comesana 7-5, 6-4.

Shelton, competing in Auckland for the fourth straight year, saved three set points while trailing 5-4 in the opening set before breaking serve and taking control.

The American, ranked eighth in the world, did not face another break point and sealed victory in one hour and 42 minutes.

"Tennis is a game of very small margins, and some days that's not going to go my way. Today, it did, and I'm just happy that I have the opportunity now to improve on some things and be moving on to the quarterfinals," Shelton said after the match.

Shelton will next face Arg...