Nine Americans, both celebrated and unsung, into AusOpen third round

MELBOURNE – After four days of competition in Melbourne at the Australian Open, nine Americans remain in contention for the year’s first Grand Slam title. While

MELBOURNE – After four days of competition in Melbourne at the Australian Open, nine Americans remain in contention for the year’s first Grand Slam title. While the Williams sisters and top-ranked American John Isner may be used to the spotlight, a small another small group of players from the states are making noise in Melbourne.

Meet the seven women and two men -- both usual suspects and unheralded contenders -- who will have a shot at the fourth round when play resumes on Friday.

Usual suspects

Serena Williams
WTA Ranking: 1
Australian Open seed: 1

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​We've seen a little bit of everything from Serena through the first two rounds. She's served up two 6-0 sets in her wins over Alison Van Uytvanck and Vera Zvonareva, but she was also down 3-5 in the first set to Zvonareva before saving set points and reeling off 10 straight games. Next up is No. 26 ElinaSvitolina.

Venus Williams
WTA Ranking: 18
​Australian Open seed: 18

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Venus hasn't made the fourth round of a major since Wimbledon in 2011. She also hasn't looked this good at a major since then. Venus has lost just one set in seven matches in 2015, cruising through the first two rounds in Melbourne. Next up is a tough opponent in the big-hitting Camila Giorgi. Her draw isn't an easy one here on out. Potential matches against Agnieszka Radwanska and Petra Kvitova loom.

• NGUYEN: Azarenka tops Wozniacki

John Isner
ATP Ranking: 21
Australian Open seed: 19

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The top-ranked American man has lost just one set through the first two rounds. He faces Gilles Muller in the third round and a win could earn him a shot at No. 1 Novak Djokovic in the fourth round. Given the problems Isner has caused for Djokovic on hard courts at ATP Tour events, this could be a big opportunity for Isner to finally make his mark at a Slam.

Unheralded contenders

Varvara Lepchenko
WTA Ranking: 30
Australian Open seed: 30

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Thanks to a strong run to the semifinals of the Brisbane International earlier this month, Lepchenko is the No. 3 American behind Serena and Venus Williams. That might surprise some given the ink devoted to the likes of Madison Keys. Lepchenko is often left out of the spotlight due to age more so than talent. Keys is a teenage prodigy, while Lepchenko is a late bloomer at 28. But this is might be the tournament for her to shine. The Uzbekistan-born lefty has a solid base and tricky game to read for many. She's into the third round with straight set wins over Vitalia Diatchenko and Ajla Tomljanovic, and she faces No. 3 Agnieszka Radwanska on Saturday. Historically, the match-up has proven difficult for Radwanska. Lepchenko has won their last two meetings, both last year on hard courts in Stanford and Seoul. If she can pull off the upset she'll play the winner of the Venus Williams-Camila Giorgi match.

Madison Keys
WTA Ranking: 35
Australian Open seed: Unseeded

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While she isn't necessarily a surprise contender or new to making headlines, the 19-year-old showed good poise to rebound from losing the first set to No. 29 Casey Dellacqua and win in the second round in Melbourne. Now comes a big test against No. 4 Petra Kvitova. The two have played just once, with Kvitova winning 6-2, 6-2 at the Toray Pan Pacific in 2013.

"I think there'll be lots of long rallies," Keys joked, referring to their penchant for high-risk, first-strike tennis. "I think it's one of those matches where we're both fighting to be the aggressor first and I think that'll just be the entire match. I think whoever wins is the who was able to do that consistently and the best."

• NGUYEN: Friday's matches to watch

CoCoVandeweghe
​WTA Ranking: 37
Australian Open seed: Unseeded

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​Recognize the last name? The California girl is indeed the granddaughter of Ernie Vandeweghe and niece of Kiki Vandeweghe. She possesses one of the most potent one-two combinations on tour, with a powerful serve and heavy forehand that can prove unplayable when she's on. She put on a top-notch performance on Thursday in a 6-4, 6-4 win over No. 20 Sam Stosur in the second round. Vandeweghe is coming off her best year on tour, where she won her first WTA title on the grass courts of s'Hertogenbosch and finished the year at No. 40. After years of struggling with her consistency off the ground, Vandeweghe has transformed into a dangerous opponent. She's shored up her backhand and her weapons have only gotten better.

The 23-year-old is into the third round of a Slam for the first time in her career and has a great opportunity to go one further. She faces fellow American Madison Brengle in the third round and the winner will face the either No. 4 Petra Kvitova or Madison Keys.

Steve Johnson
ATP Ranking: 38
Australian Open seed: Unseeded

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After a couple of years of struggle, Johnson has become a reliable early-round winner. After winning his last 72 matches in college, Johnson's transition to the pro tour was a rude awakening. For the first time in his career, he had to learn how to lose. Wins were tough on the ATP Tour, but Johnson turned the corner in 2014. After toiling away on the ATP Challenger circuit, the wins began to come on the pro tour. Now he's into the third round of a major for just the second time in his career and he gets a shot at No. 5 Kei Nishikori.

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Madison Brengle
WTA Ranking: 64
Australian Open seed: Unseeded

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​The 24-year-old from Delaware is one of the hottest players on tour at the moment and given her health scares over the off-season, it's all come as a pleasant surprise. After cracking the Top 100 last fall, Brengle was diagnosed with skin cancer in September after she noticed an unusual growth on her leg. Then after getting the all clear from her doctors, they discovered a lump in her jaw that thankfully turned out to be non-cancerous. Brengle was unsure she would be able to make the trip to Australia until her doctors finally gave her permission, and she's been tearing it up ever since.

She opened her season by making the second round of the Brisbane International as a qualifier and followed that up by making her first WTA final, again as a qualifier, at the Hobart International. In Melbourne, she upset No. 13 Andrea Petkovic in the first round and followed that up with a win over fellow American Irina Falconi to make the third round of a Slam for the first time in her career. She’s matched up against Vandeweghe for her next match in Melbourne and is already on the verge of cracking the Top 50.

BethanieMattek-Sands
​WTA Ranking: 258
Australian Open seed: Unseeded

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Ignore the ranking. Mattek-Sands is coming off an injury-stalled 2014 season and is aiming to reach the fourth round of a Slam for just the third time in her career. She scored a solid straight set wins over Kristina Mladenovic in the second round and now has a shot at No. 3 Simona Halep.