(THE GUARDIAN) - Serena Williams' coach says her recent break from the game was down to the fact she was suffering from depression and she also needed to allow her knees to recover after missing out on the calendar grand slam in September.
"She was depressed," Patrick Mouratoglou told ESPN. "The reaction was quite strong. She was really, really affected, which I think is normal when you are Serena.
"She does everything with 100% of her heart so you are more disappointed when you don't reach your goal. Plus, she has a level of expectation that is much higher than anyone."
Williams had been unexpectedly beaten in the US Open semi-finals by Roberta Vinci when it appeared that the "Serena Slam" was a guaranteed bet and Mouratoglou said they did not speak for two weeks afterwards while he allowed her to get it out of her system.
"She doesn't want to talk when she's depressed," he said. "But it's better. Because I represent tennis, and when you are [recovering] after something like this, you have to see people who don't represent tennis.
"You have to change your mind. Otherwise you keep on thinking about it. I didn't force it. I know her and I understand also that she needs a break. It's fine.
"I think it's good if she just pushes herself and she sees people and she goes out a little bit. It helps you also to think about something else. You have to erase that from your memory."
The French coach also disclosed that Williams was plagued by knee injuries similar to those that have hindered the career of Rafael Nadal.
"It's the same as Rafa," Mouratoglou said. "It's just playing for so many years, the cartilage is gone. Not all of it, but a big part, so the bones just hit themselves.
"She has bone bruises, and if you keep on playing with this for too long, too much, the next step is a stress fracture."
Mouratoglou said the break had given the injuries a chance to heal. "There was no other option, and we knew that at some point we had to do it, because she plays with pain all the time. The injury can get really worse, and at her age her career could really be in danger if she went too far and got more injured, like Rafa did in the past.
"He kept on playing with the same problem and then it got worse and he had to stop for almost a year, we don't want this to happen. She is 34, if she has to stop for a year then it is really bad for her future.
"I'm not a doctor, she has treatment, but I know without rest there is no chance because you keep on hitting the bones all the time."
Mouratoglou said her knee problems had contributed to her defeat at Flushing Meadows. "With the knees you never know, sometimes the pain is much more. That was the first thing she said when she came to the court [to warm up]: 'My knees hurt so much today.' So she was really struggling to move.
"I think also the tension went to another level, which I expected, because the closer you get to a final goal, obviously the stress goes to another level. I take responsibility on that because I couldn't find a way to make her handle it better."
