The 2014 Australian Open has already seen its share of surprises and exciting matches, but we're just getting started as the tournament is wrapping up the fourth round of action.
Serena Williams was the first huge name to go down as the American star wilted in the fourth round to 14th-seed Ana Ivanovic. The women's singles top seed was hampered by back pain after easily winning the first three rounds and could not overcome the tough test from a worthy foe.
The biggest names in men's singles have yet to be touched for the most part, but with three of the top four in men's tennis—Andy Murray, Roger Federer and Rafael Nadal—taking the stage on Day 8 against top competition, you never know who could be knocked from contention.
Day 8 boasts a handful of exciting matchups that you don't want to miss as Round 4 concludes.
No. 6 Roger Federer vs. No. 10 Jo-Wilfried Tsonga
It's not very often that matches of this magnitude and quality expose themselves before the quarterfinal round.
In fact, Federer and Tsonga met twice in Grand Slam quarterfinals a year ago. They met in the 2013 Australian Open, where the Swiss star escaped with a narrow, five-set victory. Two of those sets needed a tiebreak to decide.
Tsonga exacted revenge quite quickly, however. The French native played in his element at the French Open when he faced Federer in the quarters again and ousted him in straight sets to prove that last year's action in Melbourne may have been a fluke.
Both of these matches from last season will weigh heavy on the minds of Federer and Tsonga, who remember the other as the reason why they were knocked out of a Grand Slam somewhat early. And with Federer chasing his 18th major and first Australian Open win since 2010, there's no doubt he will be bringing his best stuff.
No. 1 Rafael Nadal vs. No. 16 Kei Nishikori
Nadal has re-emerged in the past year after falling off the pace quite a bit at every Grand Slam other than the French Open, and he looks poised to prove his top seeding is well earned against a tough foe in Kei Nishikori.
Nadal cruised in the fourth round to get here, posting a 6-1, 6-2, 6-3 victory over Gael Monfils, and looks to be playing his best tennis in recent memory. If he keeps it up and lifts the trophy in Melbourne, it would be just the second time he has done so.
The Spaniard has played Nishikori five times—winning them all—and only lost one set throughout those matches.
If recent form and history between the two are any indication, Nadal should have no problem advancing to the quarters, where the competition will go from great to insane as some of the world's best await.
No. 2 Victoria Azarenka vs. No. 13 Sloane Stephens
American tennis fans still shocked by Williams' exit from the tourney can take solace in a budding star who could put a stamp on her recent success with one of the biggest wins of her career.
Sloane Stephens, a 20-year-old American, will go up against the new favorite to win the women's bracket, No. 2 seed Victoria Azarenka in a rematch of one of 2013's most memorable matches.
The two faced off in last year's Australian Open, after the then-29th-seed Stephens ousted Williams. Azarenka won in straight sets, but not before taking a controversial medical break following five failed match points and raising eyebrows across the tennis world.
Whether there's still bad blood between the two after that incident is to be determined, but at the very least, Stephens will be looking to get some revenge and get to the Australian Open semifinals for the second straight year—quite the noble feat for someone who can't even legally drink yet.