Some players throw rackets or smash them. Others kick their chairs or scream obscenities when they get upset during a match.

Italian veteran Flavia Pennetta bites the net.

The 28th-seeded Pennetta had been beating her higher-ranked German opponent, Angelique Kerber, so convincingly in their fourth-round match at the Australian Open on Sunday that when she failed to break Kerber early in the second set, she took out her frustrations by leaning over the net and chomping on the tape.

Fortunately for Pennetta — or her dentist, perhaps — she didn't have the need to leave her teeth imprints on anything else. The Italian recovered after dropping the second set to defeat Kerber 6-1, 4-6, 7-5 and reach her first-ever quarterfinal at the Australian Open.

Pennetta, who turns 32 next month, is having the kind of late-career revival that reinforces the idea that 30 is the new 20 in women's tennis.

Since returning from a wrist injury last February that caused her ranking to drop as low as No. 166, the Italian has reached her first Grand Slam semifinal at the U.S. Open and now her maiden quarterfinal at Melbourne Park.

"Well, I think when you're old, you're starting to have different goals and try to enjoy a little bit more the life, no?" she said.

Pennetta's opponent in the quarterfinals is another thirty-something: two-time finalist Li Na, who beat Ekaterina Makarova 6-2, 6-0 in the fourth round on Sunday.

The Chinese star was quick to point out in her post-match interview, however, that she's actually younger than Pennetta. By a day.

"You know what at least she is one day older than me. So I will play older player. Not like couple rounds (before) always younger than me," she said. The fourth-seeded Li beat a pair of 16-year-olds in the first two rounds, the two youngest players in the draw.

Both Pennetta and Li were among five 30-something women who reached the quarterfinals of last year's U.S. Open, a Grand Slam record for the Open era. The others were Serena Williams, Roberta Vinci and Daniela Hantuchova.

The 32-year-old Williams failed to become the third player over 30 in the quarters at Melbourne Park when she lost Sunday to former No. 1 Ana Ivanovic.

Pennetta, who's been ranked as high as No. 10, doesn't have an explanation for why she's playing better at this stage of her career. She's happy to be playing in Grand Slams at all, considering she missed six months from late 2012 to early 2013 recovering from surgery on her wrist. She struggled when she returned to the tour, too, losing seven of her first 10 matches.

"The feeling I had was completely not good," she said. "In the beginning, the result was not good at all."

Now she's got a chance for her second Grand Slam semifinal in a row. She even has dreams of being back in the top 10.

"For the moment, it's so good, so I hope to just keep going, she said.