Serena Williams vs. Flavia Pennetta: Score and Recap from 2014 US Open

Facing as much adversity as she had all tournament, Serena Williams shrugged off a sluggish start on Wednesday at the 2014 U.S. Open.

After the women's top seed dropped the first three games to Flavia Pennetta, Williams rattled off six straight games and cruised from there for a 6-3, 6-2 quarterfinals win.

Nike Tennis fittingly articulated the way Williams rallied:

Williams entered the match feeling little pressure despite a disappointing Grand Slam season that saw her advance no further than the fourth round before this stop at Flushing Meadows.

"Now I'm more relaxed," said Williams, via USA Today's Douglas Robson. "I feel like I don't have to win any more. I've had a wonderful career."

That doesn't mean Williams is content to rest on her laurels and 17 major titles, though. For a relevant example, just bear in mind how she bounced back after being broken twice in the first three games on serve.

Before those two breaks, Williams hadn't dropped a set in the U.S. Open this year, hadn't conceded more than three games and had been broken just twice all tournament. Then she roared back, showing her superior ability and power against an outmatched Pennetta.

Ben Rothenberg of The New York Times was unfazed by the stirring turn of events in the opening set:

A key crossroads came with Williams serving up 5-3 in the first with all the momentum. Pennetta pushed her to 15-40 down, courtesy of two double faults. However, Williams rallied with three big first serves that yielded weak returns from Pennetta and booming, immediate winners from Williams.

The dawn of the second set saw Pennetta grind to hold the opening service game and then push Williams to deuce thereafter, though she couldn't capitalize on the situation.

Small victories were had along the way when Pennetta served six aces in the first two games.

That failure to break in the second game proved costly when Williams turned it on and broke Pennetta at love to go up 3-2. The fifth game of the second set all but ended Pennetta's hopes of pulling the upset, and Williams dropped just one point on serve to take a big 4-2 lead.

A seemingly demoralized Pennetta couldn't muster enough to hold serve, leaving the second set to close out much in the same way the first did.

Attacking more often allowed Williams to be successful after she looked a bit tentative in the early going. Williams wound up with 31 winners to 19 unforced errors, while Pennetta had 13 and 16 in those categories.

Slower second serves opened up opportunities for Williams to step into her returns, as she won 55 percent of her return points, compared to just 38 percent for Pennetta.

Barry Flatman of the Sunday Times weighed in on Williams' latest conquest in Flushing:

Williams will face No. 17 seed Ekaterina Makarova, who defeated Victoria Azarenka on Wednesday. Tennis View Magazine's Nick Nemeroff posted Williams' formidable record against her remaining prospective opponents:

This is Makarova's first semifinal appearance in a Grand Slam, so she figures to be a heavy underdog. Perhaps defeating a two-time reigning U.S. Open finalist in Azarenka will give her the confidence she needs to be competitive.

Being the favorite is a role Williams has struggled with at the 2014 Grand Slam tournaments until now. She let her guard down versus Pennetta, yet found a way to dig deep and dominate from there. No one is as good as Williams when she is on her game, and she's playing her best major tennis of the year.

Former top-ranked player Caroline Wozniacki is hoping to win her first Grand Slam title. Wozniacki will likely meet Williams in the final. That figures to be a finale to remember in the Big Apple, but Williams, comfortable as the perpetual No. 1, will be the prohibitive favorite.