(CNN) -- It was, the premature obituaries proclaimed, the beginning of the end for Serena Williams.
The indomitable figurehead of women's tennis had been humiliated and cowed -- turfed out of the 2012 French Open in the first round by an unheralded and unseeded opponent.
After an injury-blighted few seasons that saw her sink to 175 in the world rankings, Williams had hit one of the biggest troughs in her career.
Given all she had achieved, it would have been easy to throw in the towel -- but even at her lowest ebb, Serena's desire to clamber back to the top was insatiable.
But she needed help and, while still in Paris, she found it in the shape of coach Patrick Mouratoglou, with whom she has been linked romantically.
It was a partnership that was to restore Williams as the preeminent female player of her generation, culminating in her most successful season at the age of 32.
"What surprised me at that point was the motivation she had," Mouratoglou told CNN's Open Court show. "She really was prepared to do anything to come back to the top.
"Her motivation was at the highest point, maybe, and it was very surprising for someone who had won so much, with such a career record and at that age.
"She was struggling a bit at the time because that loss really affected her, but she was motivated to work, so that's what she did."
The results speak for themselves.
Serena has won 16 titles in 16 months, with a record of 95 victories and five defeats since teaming up with Mouratoglou.
In 2013 she won 11 titles -- including the U.S. Open, French Open and season-ending WTA Championships -- the best return in women's tennis since Martina Hingis in 1997.
Such a formidable run, which saw her pocket a cool $12.3 million in prize money this season, means she now has 17 grand slam titles to her name. Only three players in the Open era have more.
But according to Mouratoglou, it was the humbling she was served in Paris that paved the way for this current, imperious streak.
"It's a failure, you have to accept it," he explained. "When you have failure you can work to be better, and you realize sometimes it's good to come back to reality.
"That's how I see my role, to help her reduce the chances to lose to the strict minimum.
"I think the chances of her losing now are much smaller than in the past. If you look at the statistics they show it, but maybe we can do better -- and it's a real goal to do better."
That insistence Williams can reach even greater heights might make her rivals wince.
There are very few players in the modern game who can match the sheer power and intensity of Williams at her peak.
Though now in her thirties, Mouratoglou rejects any suggestions she is showing any signs of slowing down, and he thinks she can improve still further.
"For sure, she's unique," he said. "I've worked with hundreds of players and many in the top 50 men and women -- for me, I've not seen anyone like her.
"She's a real champion. It's not about the strokes, it's about what you have inside -- and she has something really special inside. The quality of the game she is able to play at her age shows how much her game has evolved from most of the players.
"I think she improved in many ways her movement on the court; she moves much better, she moves longer also, she can play longer rallies, much longer if she needs to.
"I think she added some shots to her game that she was not using that much before. She wasn't using them because she wasn't mastering them like some other shots she masters like nobody else on tour.
"I think that's a key thing -- the more options she gets on tour in her game, the more chances to win she has on the first day of the year against the player who plays the best tennis of her career.
"If she plays her type of game with more efficiency, like being maybe even more aggressive, adding some volleys, some swing volleys for example, she can give another level, which is maybe a bit frightening, but I think she can."
Mouratoglou's influence has clearly galvanized Williams, but he insists it is her desire to take responsibility that makes her so unique.
Whereas others might look in desperation to their coach for help if a match is getting away from them, Serena grits her teeth and figures it out for herself.
"She has this ability to find a solution to win, she refuses to lose and this is something really interesting," he said. "Most of the players when they are in trouble, or they are struggling, they are complaining.
"She shouldn't think, 'I have to rely on someone' to find the solution,' because she has the solution within herself. She just has to analyze, think, and dig deep and find.
"Some (players) just complain and get angry, or give up -- that's the case of many players. And some others call their coach whenever they get broken: 'Oh, I need my coach!'
"Come on, you don't need your coach every time you're broken. You have to think what you should do and look for a solution, and this is something that Serena really has in herself."
So, with Serena in supreme form, is it conceivable she could smash all records in 2014 and win all four slams -- something not done since Steffi Graf in 1988? "Yes, I think everything is possible," Mouratoglou says.
"Is it going to be easy? No, it's not going to be easy, because in terms of focus it's something really tough to achieve, and also we have to respect the quality of the other players."