MONTERREY, Mexico -- In a battle between two players who have each won two Grand Slam titles and reached the World No.1 position, it was No.2 seed Garbine Muguruza of Spain who came out the victor and defended her title at the Abierto GNP Seguros, as No.5 seed Victoria Azarenka of Belarus retired while trailing 6-1, 3-1.

Muguruza defeated Timea Babos in the 2018 final for her only singles title last year, and once again she hoisted the trophy in Monterrey for her first title of the season, when Azarenka's leg injury made it impossible for her to continue after 66 minutes of play. This is the first time Muguruza has defended a WTA singles title, and it is the seventh title of her career.

"I'm very happy with this week," Muguruza said, during her on-court post-match interview. "It's a great feeling to come back and defend a title. It's never easy. I'm loving Monterrey a lot and the crowd is supporting me all the time. "

Photos: Monterrey magic: From Bartoli to Muguruza

"Every title is sweet," Muguruza later said to the Spanish-language media. "The ending was a little strange, [Azarenka] was injured, but it's a special feeling, winning last year and now this year."

"I did have tough opponents, this year's draw was the best," Muguruza continued, "and, well, I played my best tennis."

Azarenka had won their only previous encounter, in two tiebreak sets at the 2016 Miami Open, and the Belarusian went on to win that event. This week, Azarenka reached her first final since that very tournament, picking up her first Top 5 win since then as well, in the semifinals over Angelique Kerber. But her injury and Muguruza's strong play allowed the Spaniard to level their head-to-head.

Muguruza converted four of ten break points during the truncated tilt, and she had 16 winners to 11 unforced errors. Azarenka had 13 winners to 22 unforced errors, and was unable to convert any of her six break points, which all came in the opening set.

Muguruza claimed the first set with a lopsided scoreline, but Azarenka was well into many of the games. The Belarusian, however, was unable to take her chances and pull back from her early 2-0 deficit.  Azarenka missed multiple service returns as Muguruza clawed back from 0-40 down to hold for 3-1, and Muguruza again saved three break points before holding for 5-1.

By contrast, the Spaniard powered through the close games on Azarenka’s delivery with her sturdy groundstrokes. Muguruza ended up on top in two multiple-deuce games when Azarenka was serving, at 2-0 and 3-1, and garnered a third break for good measure when Azarenka was serving to stay in the set at 5-1.

After Azarenka received treatment on her leg during a medical time-out between sets, it became apparent as the second set got underway that her movement had become significantly hampered. The Belarusian gave it her best effort to continue, saving break point to guts out a hold for 1-1.

But Azarenka was grimacing and stretching after nearly every point by this juncture, and after Muguruza swiftly broke serve for a 3-1 lead, the two-time Australian Open champion decided to stop play, ceding the trophy to Muguruza as the Spaniard picked up the Monterrey singles title for the second straight year.