Source: Twitter

Serena Williams was reeling from her first opening-round loss at a major when like an angel, Patrick Mouratoglu swooped down and hoist her up ... and up again to the top of the women's tennis.

Their partnership started simple enough. It was born from casual greetings, practice court chats and tournament conversations. But in crisis, their simple partnership became so much more.

In her struggle to regain her top position, Mouratoglu became William's part guru and part promoter. Little by little, the Frenchman became part of William's tight circle, there to oversee her games and protect her against intrigues, and ultimately, to take hold of her heart as well.

Fifteen months after Patrick Mouratoglou lent a hand to Serena Williams - then reeling from her first opening-round loss at a major - he has become the catalyst behind her return to the top of women's tennis.

"We have this great communication," Williams told USA TODAY Sports after winning her second French Open back in June. "It's definitely a two-way street. I think coaches sometimes think it's always their way. And it's like, 'You do this because I say it.' Our dynamic is not like that at all. I think that's what makes him so good. He's open to me, and I'm open to him. It creates something special."

Ever since their team was formed after the 2012 French Open, Williams demonstrated the most complete winning stretch of her career.

Mouratoglu proved why he is the best for the top woman tennis star too. Mouratoglou chatted with USA TODAY Sports this summer to talked about "very complex" personality of Williams and their good relationship, which he equated to becoming conversant in another language."If you just stick to what she says, you'd be wrong most of the time," he said. "You have to understand what's behind all of the time. You have to anticipate.""You have to learn another language," he further elaborated.

Their partnership apparently works out great. Under the Frenchman's tutelage, Willaims become a more complete player who improved statistically in almost every metric in 2013. She was just better from break points to points won returning first serve. No wonder she achieved that emphatic 6-4, 6-1 against Sloane Stephens on Sunday.

"She is mutating," Mouratoglou says. "If you look at how she was playing when she was 20 and now, it's a completely different player.

And we all have him to thank for that.