Watch: Throwback to when Serena Williams broke into tears after regaining No. 1 ranking for first time in nearly 2 years in 2013

Serena Williams' coach Patrick Mouratoglou recently took to Instagram to share a throwback video of the 23-time Major winner beating Petra Kvitova in Doha in 2013. With her victory, she returned to the World No. 1 position for the first time since 2010, which caused her to break into happy tears during her post-match speech.

Serena Williams was in the middle of a slump back in 2012. After she exited Roland Garros in the first round, the American made changes to her coaching staff, hiring Patrick Mouratoglou for her Wimbledon campaign the following month.

The partnership reaped immediate rewards as Williams lapped up titles at Wimbledon, the London Olympics, the US Open, and the WTA Finals. And despite being upset by Sloane Stephens at the 2013 Australian Open, she would go on to make tennis history at the Qatar Open in February that year.

The American reached the final at the WTA Premier event (losing to an in-form Victoria Azarenka), which ensured that she would regain the World No. 1 spot for the first time in nearly two years. In that context, Mouratoglou took to Instagram to express his elation at his ward's campaign in Doha back then, while asserting matter-of-factly that she held the top spot for more than three years after that.

He also mentioned how the 23-time Major winner thought her career was over after suffering a pulmonary embolism towards the end of 2010, which forced her to pull out of all tournaments after Wimbledon that year.

"February 2013: after 8 months of collaboration, Serena Williams comes back to World No.1, where she will stay for 3.5 years! Sometimes you might feel that you are done, but the power of belief and commitment can make wonders," Mouratoglou wrote. "Can't help being super emotional reviewing those images."

"I've been through so much, I never thought I'd be here" - Serena Williams on returning to World No. 1 in 2013

The former World No. 1 at Wimbledon in 2013.

Mouratoglou also shared Williams' post-match interview from that day, where she was overwhelmed with emotions after regaining the World No. 1 ranking.

"Yeah, I'm so sensitive nowadays, I'm always crying. I never thought I would be here again, you know, so..." she said then. "Oh my gosh, I've been through so much. I never thought I'd be here, so, thank you Jehovah for giving me another chance."

Beginning her sixth stint as the No. 1, the American went on to win eight more Major titles in her career. And while she did drop to No. 2 after losing to Angelique Kerber at the 2016 US Open, she was able to regain the top spot after winning the 2017 Australian Open in emphatic fashion. All-in-all, she has spent 319 weeks as World No. 1.