Serena Williams is arguably the greatest tennis player in history.

There wouldn't even be a debate if every one of her matches came against Maria Sharapova.

Williams continued her dominance of Sharapova on Monday with a 6-1, 6-1 straight-set victory in the first round of the 2019 U.S. Open at Arthur Ashe Stadium in New York. It was a high-profile showdown typically reserved for the later rounds of tournaments, as NBC Sports noted it was the first meeting between the pair before a round of 16.

This rivalry has been a one-sided story throughout their respective careers.

Williams now holds a commanding 20-2 advantage in head-to-head matches, with Sharapova's last victory coming in 2004. Williams also entered play with an 18-match winning streak against Sharapova, not counting the time the American withdrew prior to their fourth-round match at the 2018 French Open because of injury.

The dominance extends beyond their individual meetings. Williams is a 23-time singles major champion and six-time U.S. Open singles champion who won the tournament three times in a row from 2012 through 2014. She also reached the final last year before losing to Naomi Osaka in a memorable match.

Sharapova hasn't advanced past the round of 16 in New York since she reached the semifinals in 2012.

Still, the Russian is a five-time major champion who won the 2006 U.S. Open. She is far from an ordinary first-round underdog for Williams or anyone else, even if she has fallen to 87th in the singles rankings.

This was also the first meeting between the two at the U.S. Open, but it was business as usual out of the gates.

Williams wasted little time breaking Sharapova twice in the first set and cruising to a 6-1 win. She overwhelmed the challenger with her serve, winning a commanding 85 percent of her first-service points and never giving Sharapova a chance to close the gap in the first set.

Any realistic comeback chance was short-lived when Williams broke Sharapova in the first game of the second set and rallied from down 15-40 with four straight points to go ahead 3-1.

Williams' break in the next game seemingly put the match away, and she held off another three Sharapova break points to prevent any desperate comeback efforts. The victor broke Sharapova one more time for good measure to end the match.

In all, Williams won 78 percent of her first-service points to just 52 percent for Sharapova and capitalized on four of the five break points she created. She completely controlled every aspect of the match and appears to be well on her way to challenging for another major championship.

What's Next?

Williams will play Catherine McNally in the second round after the latter eliminated Timea Bacsinszky in straight sets on Monday.

The two Americans have never played each other but will have their first meeting on home soil.

*All stats are courtesy of the U.S. Open's official website.