Clay hasn't always been a happy hunting ground for CoCo Vandeweghe but a high-quality display against Laura Siegemund in the Mutua Madrid Open second round could change that.

MADRID, Spain - CoCo Vandeweghe continued to showcase her improvement on clay with a solid 6-2, 4-6, 6-3 win over a spirited Laura Siegemund to advance to the third round of the Mutua Madrid Open, holding steady despite letting a 4-2 second set lead slip away.

The second-round clash was an all-unseeded affair but both players had made their mark on 2017: the American with a run to the Australian Open semifinals and the German with a giant-killing Stuttgart title two weeks ago. The match was always going to be notable for its stylistic contrast, with Siegemund attempting to frustrate Vandeweghe's immense power with her bag of tricks.

"She's a tough player; she gives a lot of different variety that you don't normally see," Vandeweghe said after the match. "I had a really good, decisive gameplan and it worked well."

Perhaps surprisingly, the 29-year-old's clay proficiency counted for little initially. Vandeweghe had never won back-to-back WTA matches on the surface before today but she did own a 2-0 head-to-head lead over her opponent - both victories coming in ITF events in 2009. 

The altitude of Madrid has always favoured big servers, too - and the American encountered little difficulty in keeping the rallies short and ending them efficiently. Siegemund, meanwhile, struggled to find her range on return and even her trademark dropshot.

The pattern continued in the second set, with Vandeweghe breaking for 4-2 with a patiently constructed rally that encapsulated the progress she has made on clay.

However, Siegemund has gained a reputation for playing her best when down, and her fighting spirit came to the fore once again as she broke back with some spectacular returns. With her confidence renewed, she rode her momentum through four consecutive games to snatch the set from a visibly frustrated Vandeweghe. By now, the full range of the German's gutsy plays were being showcased, including serve-and-volleying on the penultimate point of the set.

"I think my biggest problem was that at the end of the second I was a little bit passive in my decisions of where I was hitting the ball and I kind of started to let her dictate a little bit more. At the start of the third I'd rather just win or lose on my own terms - I was confident that the game plan I had was going to work, it was just a matter of me excecuting it."

The third set saw Vandeweghe gather herself, though, particularly on serve: of her six aces today, four came in the decider. A well-timed venture to the net on return paved the way to an early break of Siegemund, and thereafter the American rode it to the finish line, snuffing out any opportunities for her 29-year-old opponent with booming deliveries. It was little surprise that she finished with a love hold - including an ace and two unreturned serves - to score her first consecutive WTA Tour victories since January.