MADRID, Spain -- Top seed Naomi Osaka of Japan picked up a main-draw win at the Mutua Madrid Open for the first time in her career after sliding past 2016 Madrid finalist Dominika Cibulkova of Slovakia, 6-2, 7-6(6), in the opening round of the Premier Mandatory event on Sunday.

"For me, I'm just happy to get through it," Osaka admitted to the press, after her victory. "I feel the most nervous during the first round and to play against Cibulkova was kind of tough for me, especially on clay."

In her only prior appearances in the Spanish capital, Osaka had fallen in qualifying in 2016 before losing to Zhang Shuai in her main draw debut last year. But now, holding the mantle of World No.1, Osaka clinched a victory over former World No.4 Cibulkova after one hour and 55 minutes of play, extending her head-to-head record against the Slovak to 3-0, and 6-0 in sets.

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The No.1 seed fired 43 winners, including eight aces, against 30 unforced errors to book her spot in the second round. World No.33 Cibulkova put up a stern fight in the second set and had 23 winners to just 15 unforced errors in the match, but the Slovak won just 51 percent of her first-service points.

"I was also kind of thinking, like, there is nowhere else I'd rather be and honestly I train for these moments so I have to give it 100 percent," said Osaka.

Osaka moves into the second round, where she will face the winner of the match between two Spanish wild cards, Lara Arruabarrena or Sara Sorribes Tormo.

Osaka's feelings about clay have improved of late. "I feel like there's, like, an adjustment period for me and it took a few years," said the world's top-ranked player. "But now I'm more comfortable on [clay]. I'm not sure if it's because I had a really long training block before I came to start the season, but yeah, it feels good."

Cibulkova claimed the initial break of the match, going up 2-1 on her fourth break point after Osaka saved the first three chances with well-timed powerful serves. Despite falling behind, Osaka’s powerful game was already working in spurts, and the No.1 seed quickly broke back with a backhand crosscourt return winner, leveling the set at 2-2.

That opened a run of five straight games for Osaka, who mainly ended up on the winning end of big-hitting rallies to break Cibulkova twice more in succession. Cibulkova nearly eked out a service hold in the final game of the set with crafty court coverage, but Osaka eventually claimed that four-deuce game to take the one-set lead.

A tremendous tussle then occurred in the second set, which Cibulkova opened by breaking Osaka with a winning dropshot. The Slovak used the dropshot to excellent effect in the set, as she deployed that play frequently en route to maintaining her break advantage through 4-3.

But Osaka finally regained parity, breaking back for 4-4 after Cibulkova double faulted while facing double break point. The combatants kept up their aggressive hitting throughout the remainder of the set as they moved towards the tiebreak without any further struggles on their respective serves.

In the breaker, Osaka picked off Cibulkova’s first four service points as the top seed opened up a 5-2 lead, but Cibulkova used a forehand winner and another error-forcing dropshot to get back on serve in the tiebreak, eventually pulling back to 5-5. 

Osaka fired a forehand to queue up a first match point at 6-5, but a Cibulkova crosscourt forehand winner erased that chance, as the tiebreak hit 6-6. Osaka, however, was able to claim a second match point via a strong serve, and she converted that opportunity by ending the next rally with a solid backhand for the win.