Welcome to the start of our coverage of the WTA Championships in Istanbul. First up in the round robin on day one is Agnieszka Radwanska v Petra Kvitova.

Up next: Serena Williams v Angelique Kerber at 5pm UK time.

What did you think of that match? Can Radwanska be a threat here?

RADWANSKA 6-3 6-2 KVITOVA - GAME, SET AND MATCH - Radwanska races 40-0 up with winners. Kvitova saves one of the three match points by coming in close and a second also goes begging for the world number four with a winner from mid-court. However a third ace of the match for the Pole gives her an opening win.

RADWANSKA 6-3 5-2 KVITOVA - BREAK - One game from victory. Wide from Kvitova at 15-30 down and Radwanska quickly has two break chances again. Excellent defending as Kvitova moves in - and the Pole is rewarded as the Czech fires her forehand well out under little pressure!

RADWANSKA 6-3 4-2 KVITOVA - BREAK - Kvitova finds her range to fight to 0-40 up on Radwanska's serve and has one break back with a fabulous attack and smash. Can she come back?

RADWANSKA 6-3 4-1 KVITOVA - BREAK - Radwanska a set and double break up. Poor smash into the net from Kvitova then Radwanska earns two break points with a net approach and volley. A controlled winner from the left-hander saves the first of them but her resistance falters on the next point.

RADWANSKA 6-3 3-1 KVITOVA - Brilliant from Radwanska, who follows one of those crouching winners with an ace for 40-0 then completes the love game. She has played 74 (57-17) matches so far this year, the most she has ever played in a single season.

RADWANSKA 6-3 2-1 KVITOVA - BREAK - Kvitova with a clever volley after Radwanska's shot comes off the netcord, readjusting her body. But again she lets herself down with a fourth double fault for 30-30... and a fifth for 30-40! She saves the break point with a winner having gotten the next first serve in, but two mistakes makes it a third break in three games in this set.

On that note, you can watch all the action from the WTA Championships in Istanbul on British Eurosport or online.

RADWANSKA 6-3 1-1 KVITOVA - BREAK - Too much time for Radwanska on a smash as she hits wide and Kvitova goes on to earn two break points thanks to more uncharacteristic errors from the Pole. And the break back follows. Simon Reed, commentating for the telly today, said recently that "if the big-hitters have an off-day, Radwanska gets in there, as we saw at Wimbledon; but if they are playing well, I just don't think she stacks up".

RADWANSKA 6-3 1-0 KVITOVA - BREAK - Radwanska now has four games in a row as Kvitova serves a double on her way to being broken again.

Kvitova won the 2011 event on her debut without losing a match. She has a 5-0 record. Serena Williams has the next best record (15-5) while Maria Sharapova follows (13-7).

RADWANSKA 6-3 KVITOVA - SET - Radwanska seals the set on her third chance as Kvitova's slump continues (with the odd winner, naturally...) /// @AntonClarke1: "If Serena Williams is fit and healthy she beats everyone else with ease. Its that simple!" And certainly Kvitova on today's evidence! A frustrating player.

RADWANSKA 5-3 KVITOVA - BREAK - Shaky start from Kvitova as she goes 0-30 down before she battles back to 30-30. At break point up Radwanska saves one bomb but the one that follows to the opposite corner is too much. But more errors as Kvitova loses her bearings again sees the Pole go a break up and one game from taking the opening set.

RADWANSKA 4-3 KVITOVA - Radwanska fights back to retake the lead with a hold. Kvitova coming in close but some tennis savvy from her opponent gets her back in the swing of the match.

Is Radwanska going to be swept aside here? Can Kvitova challenge Serena Williams for the title, or is the American on another level? And is Eva Asderaki also your favourite umpire?

RADWANSKA 3-3 KVITOVA - There is a sea change in the confidence levels of the two players. Radwanska, except for a superb drop shot, looks harried while Kvitova is throwing herself into her strokes. Before this game the proportion of shots takes inside and behind the baseline were 7-93 for the Pole - somewhat defensive! - and 46-54 for the Czech.

You can watch all the action from the WTA Championships in Istanbul on British Eurosport or online.

RADWANSKA 3-2 KVITOVA - BREAK - Much better from Kvitova! She thunders a forehand winner for 0-40 and, after Radwanska saves the first, dominates the following point to get back on serve. Radwanska has converted 1/9 break points, her opponent 1/2.

RADWANSKA 3-1 KVITOVA - Kvitota gets away with this game and is now on the board. A double fault gives Pole Radwanska three break points before a rare error - and another! - save two of them... and an ace saves the third. A fourth break chance goes begging and Kvitova holds enough of her frayed nerves together to seal the hold.