MIAMI, FL, USA - Top singles threats Victoria Azarenka and Ashleigh Barty have each enjoyed some stellar doubles success over their careers, but it wasn't until last summer that the two considered joining forces for the upcoming 2019 season.

GALLERY: Ascending in Acapulco - The best photos from Mexico

"The first time the idea sparked was at the US Open," the former World No.1 explained after she and Barty outlasted Aleksandra Krunic and Alexandra Panova in a match tie-break. "I asked Ash if she ever wanted to play. We'd had a great practice, and we thought it could be fun because she has a really cool personality.

"I like to play with someone is also fun on the court. The Australian Open was an opportunity to play together, and hopefully we’ll continue some more."

"I think we complement each other well. I think we also know that we’re both flexible, and can chop and change if we need to. We can change sides, change serves. We both have versatile games when it all clicks together."

- Ashleigh Barty

Azarenka has made a combined seven Grand Slam doubles and mixed finals - winning two in mixed along with an Olympic Gold medal with Max Mirnyi in 2012 - while Barty won her first major title at in Flushing with CoCo Vandeweghe. They made their team debut at the latter's home major, and though they played just two matches in Melbourne, Barty felt the two were onto something special.

"We complement each other well. I think we also know that we’re both flexible, and can chop and change if we need to. We can change sides, change serves. We both have versatile games when it all clicks together. That’s really exciting, even though we’ve only played four matches together.

"If she’s feeling what she wants to do, I let her do that, and vice versa," Azarenka echoed, adding with a laugh, "We kind of know how to play tennis, so it’s not that difficult!"

They reunited for the Miami Open only to find themselves with the toughest possible draw, facing Barbora Krejcikova and Katerina Siniakova - 2018's WTA Year-End World Co-No.1s.

"It was like ‘Ok, not an easy first round!’ But we played really well, stayed solid," Azarenka said of their 6-3, 6-7(1), 10-7 win over the top seeds. 

Back on court Sunday afternoon, they won six of the final seven points in the match tie-break to knock out Krunic and Panova, and reach their first quarterfinal together.

"It’s about keeping it simple, being aggressive, and a little bit of it was execution for us in the end," Barty said. "We were doing the right things, but not quite executing at times. We had a really good finish to the tie-break."

For Azarenka, it's another accolade after winning her first title since giving birth to son Leo at the Abierto Mexicano Telcel alongside Zheng Saisai.

"Right now the match experience, the playing, for me, it's all good practice," she said after a tough singles win over Dominika Cibulkova on Wednesday. "I'm trying to build the confidence, trying to build the momentum, singles or doubles. It helps both, because there is no other practice like match practice."

At 22 and playing for a first Premier Mandatory quarterfinal on Monday against No.7 seed Kiki Bertens, Barty has long used doubles to assist her rapidly rising singles game, thinking back on her run of three straight Grand Slam runner-up finishes alongside Casey Dellacqua in 2013.

"I think it’s a chance for both of us to practice serves and returns, play in pressure moments. You can’t practice those things, and so you need to be on a match court to be able to do that.

"My doubles has helped me immensely during my career, not just in the last two or three years, but even a few years back. It helped me learn my way around the tour, and it is a lot of fun out there when you find someone you enjoy playing with."

Azarenka agreed, adding that doubles is not only an added bonus on this level, but also a requirement for those getting into the game for the first time.

"I think it’s important for children to play both singles and doubles to develop volleying skills because in singles, you might not have the same opportunity to practice them in this era of speed. It’s really good, learning to diversify your skills."

Aiming to continue playing into the clay court season, the two-time Australian Open champion hopes a strong result with her Aussie partner will similarly aid in her singles comeback.

"We have seen that in last couple of years with some young players who haven't been showing some results, all of a sudden, boom, there is that momentum.

"I'm looking for that momentum, but I'm trying to build that mountain with one stone at a time to be able, when I do go up, to stay there, and not just have flash results."

Azarenka and Barty next play doubles specialists Darija Jurak and Raluca Olaru for a spot in the semifinals on Monday.