By Kim Douglass
© Mark Peterson/Corleve

(January 20, 2011) It was the best of times and the worst of times for some players on day four of the Australian Open. Where some showcased their talents in full effect others only seemed to falter and disappoint their greatest critic, themselves. Former No.1 Jelena Jankovic falls into the later group, losing her match to China's Peng Shuai.

The seventh-seed went down in straight sets 7-6 (7-3) 6-3 in second round battle. This loss comes after her opening round victory against Alla Kudryavtseva, leaving behind her six-match losing streak.

"I mean, as a top player -- I've been number one in the world -- it's tough to sometimes accept those mistakes. Really at times I couldn't believe I can do that, why am I doing that?"

During the 62 minute match, Jankovic made 39 unforced errors and squandered a 4-1 lead in the first set before regaining her footing and pushing Peng to a tiebreak. Breaking at 4-2, the No.54 player lead in the second set and served to an easy victory only three games later. Next, she will face Japan's Ayumi Morita in the third round in matched being called the "Grand Slam of the Asia/Pacific".

Meanwhile, Second-seeded Vera Zvonareva got her match against Serbia's Bojana Jovanovski off to a shaky start. Though she bounced back and was able to win 2-6, 6-3, 6-1, it wasn't until the second set, which took only 47 minutes, where she got 52% points on her first serve that the No.2 player showed signs of the athlete that made it to the finals of the 2010 US Open.

Delivering the big upset of the day, Russia's Nadia Petrova defeated, home favorite, Alicia Molik of Australia in straight sets, 6-4 6-1. Though she came out of the gate strong and determined, Petrova gained her momentum during the second set breaking the Australian to gain a 5-0 lead. Though Molik made efforts to hold on to her sixth game of the second-set, Petrova held on to her serve in the next game leading to her victory.

As for the men, Rafael Nadal wasn't the only match to stay glued to today. No.10 seed Mikhail Youzhnymanaged to make it through his five-set, 6-3 6-1 5-7 4-6 6-1, match against Blaz Kavcic of Slovenia. Delivering a "tweener" shot a la Roger Federer, Youzhny lit up the tournament and now moves on to the third round.

Also moving on is Marin Cilic who beat Santiago Giraldo, 6-3 7-6 6-1. However, fellow seed Michael Llodra is now out of the Open after losing to 20-year-old Milos Raonic of Canada in straight sets, 7-6 6-3 7-6.

Currently, things are heating up on the men's court with American John Isner closing the 4-6, 6-4, 5-2 gap between he and Radek Stepanek, Robin Soderling is off to a good start against Gilles Muller, 5-3.

More pictures from Day 4