Radwanska and Peng--together again as you always wanted to see them

Agnieszka Radwanska and Peng Shuai are incapable of stepping onto a tennis court together and quickly getting off. Every time they play one another, it's a knock-down, drag-out affair, with no shortage of entertainment for spectators. Old habits die hard: You can expect Peng to work extra hard to overcome her lack of a strong serve, you can expect Radwanska to have a very poor second serve, and you can look for Peng to most likely let match points slip by.

That was the case in the Australian Open round of 16 match which Radwanska won 7-5, 3-6, 7-5, but only after two hours and 44 minutes of tough, and often frustrating, competition. Radwanska, who became error-prone and passive in the second set, went up 3-1, 40-0 in the third. There was a questionable line call, and maybe that threw her off her rhythm, or maybe it was just inevitable that she and Peng drag the set out as long as possible. At any rate, Radwanska was broken in that game. Peng served for the match at 5-4, and Radwanska saved two match points. Finally, Radwanska won, on her second match point.

Radwanska wasn't even supposed to be in Melbourne. After having surgery in October for a stress fracture in her foot, she was told she could return to the tour in March, and that there was a one per cent chance she could play in the Australian Open. The straight-faced player from Poland provided the biggest laugh of the first week (and probably of the tournament) in an earlier round, when her racquet head flew off in the middle of a rally. After her fourth round match against Peng, Radwanska can probably be declared an official safety hazard: During the match, she hit a return which smacked a ballboy right in the head. Radwanska stopped play, checked on the ballboy, and shook his hand. Apparently, there was no real harm done.

Other round of 16 matches weren't as eventful, but they were certainly worth watching. 2nd seed Vera Zvonareva gradually worked her way into her match against Iveta Benesova, and eventually built up enough momentum to completely dominate the Czech player. Benesova, who had taken out two other Russian seeds, lost control of her serve, most likely because she was done in by the occasion. Zvonareva defeated her 6-4, 6-1.

And then there was Petra Kvitova, who defeated Flavia Pennetta 3-6, 6-3, 6-3. Pennetta served extremely well in the first set, and looked as though she might make short work of the rising Czech player. But in the second set, Pennetta did not serve as well, and Kvitova's confidence shot up. The longer they played, the more deadly Kvitova's shot-making became, and she wore Pennetta down. Kvitova made 43 unforced errors, compared with Pennetta's 33. However, she also hit 46 winners, compared with Pennetta's 16. (You might call her the anti-Woz.)

A notable upset occurred in the junior girls' competition on Monday. Kanami Tsuji of Japan defeated top seed Daria Gavrilova 6-4, 6-3. Gavrilova won the U.S. Open in juniors, and also won a gold medal at the inaugural Youth Olympic Games.