WTA Finals:Flavia Pennetta bt. Agnieszka Radwanska

Big fist pump & smile from @Flavia_Pennetta 💪😀 It's her 1st career #WTAFinals win! https://t.co/9T5uNdrJ2a
— WTA (@WTA) October 27, 2015

She's done it!! Flavia Pennetta beats Agnieszka Radwanska in straight sets to stay alive in the championships!

It's gone completely the other way as Radwanska takes the game instead. 5-4 to Pennetta, who is serving for the match.

Match point for Flavia Pennetta.. and we're back at deuce!

The Italian is thundering through! 5-3 to Pennetta, although it's game point for Radwanska, who could narrow her lead.

5th ace of the match for Flavia Pennetta, who takes a sensational lead! Up 4-3 in the second set now.

Break point as Pennetta looks to seize the lead!

The pair have played 8 times before, but it's been 7 years since any of their matches went to three sets.

Can an out-of-form Pennetta pull off this victory and keep her tournament hopes alive?

Back from a break in play, Pennetta will look to capitalise on newfound momentum. She's equalised at 2-2 in the second set.

There is a break in play as @flavia_pennetta receives some medical attention in the 2nd set. #WTAFinals pic.twitter.com/tJK3yNTWON
— TODAY Sports (@tdysports) October 27, 2015

3 game points! Agnieszka Radwanska SERVES to lead 2-1 in the second set.

.@Flavia_Pennetta wins the tie-breaker 7-6(5) to take the opening set! Keeps #WTAFinals Semifinal hopes alive! https://t.co/CLrsvhVEwD
— WTA (@WTA) October 27, 2015

Success for Pennetta! She takes the first set after a tiebreak. The winner of the first set has won every match, a good stat for the Italian to keep in mind.

First set tiebreak for Radwanska-Pennetta. The winner of the first set has gone on to win all their matches. More: https://t.co/KeqNg2kgIC
— WTA Insider (@WTA_insider) October 27, 2015

And Pennetta hasn't managed to take the set. First set tie-break for the pair.

The tables have turned! Flavia Pennetta now takes the LEAD! 6-5 to the Italian.

She's really going for it. Pennetta equalises, with the pair now 5-5 as she serves.

Game point and Pennetta ensures she's still in the set. 5-4 to an on-serve Agnieszka Radwanska.

Pennetta had gained some momentum, but now appears to have lost it. Radwanska capitalises on her lead, making it 5-3 and takes the point with a great ace!

2 break points.. and game to Agnieszka Radwanska! She's up 4-3.

The Italian has equalised 3-3 in the first set.

Flavia Pennetta is fighting to stay alive in the tournament - a must-win for her today in Singapore, and she's going out all guns blazing against Radwanska.

Pennetta needs to at least win a set to keep her chances of making the semis alive
— Reem Abulleil (@ReemAbulleil) October 27, 2015

The Italian shortens Radwanska's 3-1 lead to 3-2 with a solid fight back.

A little over 8 minutes into the match, and Pennetta has her first game! 2-1 to Radwanska, who is now on serve.

Polish Radwanska has taken the first game of the match, and is on her second game point to take the second as well.

Despite her Grand Slam win, Pennetta has not been in the best of form recently, so Radwanska is the favourite going into the match.

This is Pennetta's last year in competitive tennis, however, as she announced at Flushing Meadows that she would retire.

World No. 6 Agnieszka Radwanska has a tough opponent in Flavia Pennetta, who beat compatriot Roberta Vinci for the US Open title this year.