Zarina Diyas of Kazakhstan claimed a win over one of the Miami Open's best performers when she ousted three-time champion Venus Williams, 6-2, 7-6(10), on opening day of the WTA 1000 event.

"I’m very happy with the win today, it was very tough," Diyas said on-court after her victory. "Venus, I looked up to her when I was little, she’s such a legend. So for me, it’s a really special win today."

World No.89 Diyas had lost her lone previous meeting against former World No.1 Williams, which came in Cincinnati in 2015, but reversed that result in an hour and a half on a breezy Tuesday in Miami.

Diyas has a positive win-loss record in Miami, though, and improved her main-draw win-loss record at the event to 7-4 after toppling seven-time major champion Williams. Diyas's best result in Miami is a run to the round of 16 in 2018.

Williams, who earned the Miami title three times in a four-year span (1998, 1999, and 2001), is still the second-most-winningest player at the event, with a 67-17 win-loss record. She trails only her sister Serena, who is 76-9.

A brisk first set went Diyas’s way as Williams’s 16 unforced errors overwhelmed her seven winners. By contrast, Diyas kept her sheet relatively clean, with eight winners to just seven miscues. Diyas broke Williams three times in the opening frame and found a series of down-the-line winners to grab the lead.

Williams charged ahead in the second set, improving her movement to break for 3-1, then consolidating with a blistering ace to open up a 4-1 lead. Diyas, though, drew errors from the American’s racquet to wrest the break back and keep the set competitive.

Diyas failed to serve out the match at 6-5, as Williams broke back with a forehand winner down the line to queue up a tiebreak. In the breaker, Diyas squandered two match points, at 6-5 and 7-6, with errors, but Williams also hit miscues on her two set points at 8-7 and 9-8.

A forehand winner off the netcord gave Diyas a third match point at 10-9, but Williams kept the fascinating tiebreak alive with a bold backhand winner to reach 10-10. However, Williams hit an untimely double fault to cede a fourth match point to Diyas, and the Kazakh took that chance after a netted forehand by Williams.

"I’m really happy how I handled the tiebreak," Diyas said. "It was a lot of nerves, but happy I did it."

2021 Miami Highlights: Diyas defeats 3-time champion V. Williams

In earlier matches on the Grandstand, two rising 16-year-old Americans, Robin Montgomery and Katrina Scott, made their Miami Open main-draw debuts, but neither was able to notch a win against experienced WTA veterans.

Montgomery, the youngest player in the draw at 16 years and six months old, fell to two-time WTA titlist Magda Linette, 6-1, 3-6, 6-0. World No.50 Linette was contesting her first match of the season, having missed the first two-and-a-half months of 2021 due to a knee injury.

Scott, three months older than Montgomery, lost to former Top 25 player Sorana Cirstea, 6-2, 6-2. Cirstea, who made the Miami round of 16 in 2013, won 63 percent of points returning Scott's second serve en route to the win in exactly one hour.

An all-American battle wrapped up Grandstand play for the day with Shelby Rogers defeating Madison Brengle 6-3, 6-3 in 67 minutes.

"I’m really happy to get through that one, she’s a really tricky player," Rogers said in her on-court post-match chat. "She gets a lot of balls back and makes you play one more ball every time."

"It’s actually my first win at this site," Rogers continued. "The last time I was here, I was spectating, as an injured person! So I’m very happy to be here."

Rogers slammed four aces and won 80 percent of her first-service points, which allowed her to save all three of the break points she faced in the encounter.

World No.52 Rogers will now face No.5 seed Elina Svitolina in the second round.

Ajla Tomljanovic also booked a meeting with one of the highest seeds after her 7-5, 6-0 victory over Anastasia Potapova. Tomljanovic will meet No.2 seed Naomi Osaka in her next match.

In other first-round results, Barbora Krejcikova, a finalist last month in Dubai, outlasted Anna Blinkova, 6-1, 3-6, 6-3. Krejcikova, one of the highest-ranked unseeded players at World No.39, sets up an intriguing second-round battle with reigning Roland Garros champion Iga Swiatek.

Also on Tuesday, former Top 15 player Kaia Kanepi powered past Lauren Davis, 6-3, 7-5, and last year's WTA Newcomer of the Year Nadia Podoroska ousted Mayar Sherif, 6-3, 6-1.