INDIAN WELLS, CA, USA - Victoria Azarenka found her vintage form on a cool Friday night at the BNP Paribas Open, playing her part in an absolute thriller which saw her good friend and rival Serena Williams edge out a 7-5, 6-3 win in the second round. 

Locking horns with Serena for the first time since the 2016 final here in the desert, Azarenka leaves Indian Wells with her head high and a bushel of positives to take to the Miami Open. 

"As much as she's the toughest opponent I have ever played in my life, she's my favorite person to play against," Azarenka told reporters. "I feel that, for me, why I still play is because I enjoy the challenges. If it's easy, if it's boring, I don't want to play."

"But those type of challenges always motivate me. Serena is one of those players that I always look forward to play. "Again, maybe not in the second round, but my draws have been amazing my whole career," Azarenka said with a rueful smile. "There is no surprise about that."

As It Happened: Serena edges past Azarenka in second-round thriller

For over two hours, the two former No.1s played one of the highest-quality pairs of sets this season. Of the 21 games played, 12 went to deuce. In the end it was Serena who came up with the goods in the clutch to extend her head-to-head against the Belarusian to 18-4.  

"I feel like I have been improving from week to week after Australian Open," Azarenka said. "I thought I took a pretty good step forward in Acapulco even though I didn't do the results that I wanted.

"It's the little pieces, you know. There is nothing big that is missing in my game. It's really about putting those things together. Today I was able to do most of the times that. Sometimes you play against the best player in the history, and they're gonna push you.

"But as I always said, Serena pushes me to play my best tennis. I thought that today was a good match. Definitely a lot of high quality. I don't feel there was really a loser in this match. She really won. She deserved to win.

"She played better on those important moments. I felt that every game was ad, deuce, ad, deuce. It was all about who was going to take that chance, and she took them a little better today."

In the end, Azarenka fired 25 winners to 24 unforced errors, while Serena tallied 39 winners to 45 unforced errors. The quality of the shot-making was astounding, worth of an extended highlight reel that showcased just why their second-round encounter was so highly-anticipated. 

"She's a very good friend," Serena told reporters. "I would say we're pretty close. We're both moms, and we know how hard it is and how hard it's been for us to come back, starting literally from scratch and fighting our way back.

"It's been an arduous road, and I think we both really appreciate both of our efforts to do the best that we can do."

After the incredibly intense match the two greeted each other at the net with a knowing smile, with Azarenka kissing Serena on the cheek before the two hugged and exchanged encouraging words. 

"I think it's not a surprise that we have mutual respect and love off the court," Azarenka said. "On the court it's a fight. It's a war. It's a lot of intensity. But after the match, it's over. After the match, that's it. Whoever won, you know, congratulations. 

"I think it was quite an amazing match. I hope people enjoyed watching it. I hope we can do some more of that, because that's what tennis is about today. And having such a match on International Women's Day, I felt that was really incredible."