Janko Tipsarevic, currently ranked No. 372 in the world, was granted a wild card into the Houston main draw and has been making the most of it.
On Tuesday, he defeated last year’s runner up Tennys Sandgren in straight sets. On Thursday, he took out world No. 55 Cameron Norrie, 6-3, 6-4, to advance to the quarterfinals.
Tipsarevic is still very early in his comeback, with Houston marking his third ATP event of 2019. The 34-year-old didn't compete at all between the 2017 US Open and this year's Australian Open. He underwent seven surgeries in the last five years including on a benign tumor on his left foot, his right knee and both of his hamstrings.
The sunglasses-wearing Serb will face Sam Querrey on Friday.