By Richard Pagliaro | Tuesday, June 21, 2016

Serena Williams wears headphones when she walks on court, but can still hear the footsteps of her pursuers.

The reigning Wimbledon champion has not won a Grand Slam title since she defeated Garbine Muguruza to raise the Rosewater Dish last July. Williams' quest to make history will get even harder, says Hall of Famer Chris Evert.

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In addition to the pressure of chasing history, Evert points to two primary obstacles in Williams' quest to capture her 22nd career Grand Slam title to equal Steffi Graf's Open Era record.

1. During the past year, Williams hasn't showed the rousing comeback spirit she's displayed throughout her career.

2. Williams' aura of invincibility has been stripped away empowering elite opponents with more self belief.

"My observation when I'm calling her matches is two fold," Evert told the media in a conference call today to promote ESPN's Wimbledon coverage. " What I'm seeing is the fact that in the last three Grand Slams she hasn't been able to get herself into the next gear when she's in trouble. This is what she's famous for her whole career. We haven't seen that."

The six-time Wimbledon champion currently holds a 1,564-point lead over the second-ranked Muguruza.

Prior to sweeping Williams in the Roland Garros final, Muguruza said given the numbers and Serena's advancing age, "it's a matter of time" before Williams is displaced from the top spot.

"I think it's just a matter of time, honestly," Muguruza told the media in Rome. "There is a lot of players out there fighting for it, and Serena eventually is going to, you know, go a little bit down because she's like forever there. So we'll see."

Evert asserts the fact opponents are so vocal about displacing Williams from the top spot shows their growing self belief and their sense the 21-time Grand Slam champion is no longer untouchable in major matches.

"The other thing, maybe more important, is the belief from the other players," Evert said. "That's what (Angelique) Kerber talked about. That's what Muguruza talked about. They are starting to believe they can beat Serena and we haven't seen that in Serena's career when she's been dominant.

"It's two fold: It's Serena and it's the field having that belief. The Kerbers and Muguruzas have talked about that belief. And as Serena loses more and more she becomes less and less untouchable."

The ESPN analyst suggests Williams' frayed nerves have been a factor in her Australian Open  final loss to Kerber and Roland Garros defeat to Muguruza.

"I think it has gotten to her a little bit nerve-wise, no doubt about it. Especially against Kerber and against Muguruza, she wasn't able to dig herself out of the hole like she has in past years, which was surprising to see that, because that's what she is infamous for," Evert said. "When Serena's down, she can get that next gear, that next level, play some great tennis. We didn't see that in both those matches when she was in trouble. That tells me something is holding her back, and it could be nerves….

"In the last few years, she's been good enough at 60 percent, 70 percent to win matches. Now I don't think it's going to win matches for her.  The competition has gotten better. They're less intimidated by her. They have strategy when they go out against her. They're just not intimidated. They know she's human.”

Despite the diminished gap between Williams and the rest of the pack, Evert is encouraged by the top seed's preparation for this Wimbledon and believes she can win. Williams did a week of work-outs with her trainer, Mackie Shilstone, in Palm Beach before arriving in London early for a week of pre-Wimbledon practice on grass.

"In saying that it sounds like a negative for Serena, but for her to even be in this position is historical," Evert said. "I believe she can still get that one (Grand Slam title) which would tie Steffi. She did have a big week with Mackie Shilstone last week in Palm Beach and they did go over a lot of fitness. Hopefully, that was a green flag saying: I want to go that extra mile, come visit me. That's a good sign for her."