Four for four: another victory over American Shelby Rogers in 2021 gave top seed Ashleigh Barty a winning start on Thursday at the Mutua Madrid Open. 

Fresh off her third title of the season at last week's Porsche Tennis Grand Prix in Stuttgart, the world No. 1 sparkled in a 6-2, 6-1 first-round victory, adding Madrid to the list of locales at which she's gotten the better of the American this year. 

"I've played Shelby many times this year... and it's always a very big challenge," Barty said on-court after the match. "I needed to make sure that I was at my very best to be able to compete today."

After two wins against Rogers in Melbourne, at the Yarra Valley Classic and Australian Open, and another last month on Charleston's green clay at the Volvo Car Open, Barty put in her best performance of the four to earn her 13th win in her last 14 matches, and 12th straight on European clay.

Barty serves up Rogers win in opener: Madrid Highlights

Needing three long sets — a 7-6(3), 4-6, 6-4 decision in Charleston that lasted nearly two-and-a-half hours — to win their lone previous meeting on clay, Barty's level never wavered in exactly 60 minutes on court.

"Each one is different. Each one presents different challenges, different conditions. The rate that we're going, we'll play every month this year, just make it a tradition. We play each other once a month," Barty reflected in her post-match press conference.

"Every time you step out on the court against Shelby, you really need to be switched on, play your very best because she has the ability to take the match away from you very quickly. It was important for me to start well, across the whole match. It was always going to be a big factor."

Her dominance was helped by stellar serving: landing 76 percent of her first serves, the Aussie recorded eight aces, lost just two points behind her first serve in all and never faced a break point. Off the ground, the world No.1 struck 19 winners to just nine unforced errors — nearly the inverse of Rogers' line of nine winners and 20 unforced. 

Barty will next face Slovenia's Tamara Zidansek, who ousted Hsieh Su-wei in straight sets for the second time in the span of two days. After beating Hsieh in the final qualifying round, 6-1, 6-0, on Wednesday, Zidansek earned another 6-2, 6-4 victory after the 35-year-old from Chinese Taipei who entered the draw as a lucky loser.

Barty was not the only former French Open champion to advance to the second at the expense of an American player in the late afternoon: No.14 seed Iga Swiatek needed just 67 minutes to ease past Alison Riske, 6-1, 6-1.

"I always miss clay. I'm always sad that it's only, like, not even two months during the season when we're playing on clay, so I would like to appreciate every moment on this surface."

- Iga Swiatek on her return to clay

Swiatek was playing her first match on clay since winning in Paris last fall, while Riske was contesting just her second match of the season overall after overcoming a foot injury. In her first career main-draw match at the Mutua Madrid Open, Swiatek struck 27 winners and 22 unforced errors, and broke serve five times while never losing her own.

"Today I just wanted to play solid and to use all the tactics, the clues that my coach gave me to implement everything in my game that he told me. I did that pretty well," Swiatek said.

"I did some unforced errors that I wish they didn't happen, but they didn't have much influence on the score. Also I try to come back to the solid game, so I did that pretty well."

The Polish No.1 last played singles four weeks ago at the Miami Open, where she was beaten by Ana Konjuh in the third round, though she reached the doubles semifinals with Bethanie Mattek-Sands.

"It wasn't a long time off, so it's pretty normal... It was like two weeks, I guess. I had to do some sponsor stuff, photo shoots. I had a lot of things to do that I didn't need to do before. That's my new life," Swiatek said.

"For sure I needed little bit of break for my mentality because I felt like I was on tour for a long time. Even though I lost in Miami in third round, I still played doubles. We decided we're going to train here. I had six days of really hard training. I still feel that in my legs... It was like a mini pre-season.

"[It's] my first time here. For sure the balls are going pretty high because of the air here. Madrid is elevated. It's totally different. I strung my racquet more tight. I think most of the players are doing that, so it's not something special.

"You just have to be ready for every shot because I felt that on practices and even today, that when I did something like a small mistake technically, the ball went out two meters. You really have to be careful here and just kind of really, really focus on techniques."

Photo by Jimmie48/WTA

Up next, Swiatek will face a dangerous clay-courter in her own right in former Top 30 player Laura Siegemund. The German took out Kateryna Kozlova in a clash of qualifiers, 6-4, 6-2.

"I think I'm going to need to just actually get more matches on clay," Swiatek said. "Even though last time I played, I won French Open, I played eight singles matches on clay last year, so it isn't a lot. I still need to find some rhythm."