WTA Finals:Maria Sharapova bt. Flavia Pennetta

Flavia Pennetta has just played the final match of her professional tennis career.

Sharapova beats Flavia Pennetta in straight sets - 7-5, 6-1 to send Agnieszka Radwanska to the semifinals at the WTA Championships.

Invincible! Maria Sharapova wins the second set 6-1 to take the match!

Pennetta commits her 3rd double fault of the match, down 4-1 to Sharapova.

And on her 2nd serve, Sharapova hits an ace! It's her 7th of the match so far.

Has it really been 11 years since Sharapova won the #WTAFinals?!
— Matt Trollope (@MattyAT) October 29, 2015

#Pennetta starting to get fired up from errors on the racquet of #Sharapova now. I guess she has to take what she can get right now.
— Rayce Manger (@dandiophile) October 29, 2015

Pennetta holds to stave off Sharapova, who's now at 3-1.

A 6th ace for Maria Sharapova, who takes the first 3 games in a row.

Sharapova holds for the first game and breaks Pennetta for the second. She leads the Italian 2-0 in the second set.

.@MariaSharapova takes the 1st set off Pennetta 7-5! Pennetta must win 2nd set for spot in #WTAFinals Semifinals! https://t.co/9SPIR81RT7
— WTA (@WTA) October 29, 2015

Come on!!!! 💪 From 1-3 to winning the set! Maria Sharapova takes the opening set 7-5 over Flavia Pennetta #WTAFinals pic.twitter.com/JDyECARdfA
— Rodri #SharaFamily (@SharapovAce) October 29, 2015

The second set is a must-win for Flavia Pennetta. If she fails to win a set, Agnieszka Radwanska will progress to the semi-finals.

Sharapova breaks! She takes the first set 7-5.

With some strong serves today, Sharapova leads Pennetta 6-5. Can she break Pennetta, or will this go to a tiebreak?

Pennetta takes it! The two are now level at 5-5 in the first set.

Sharapova's first serve % of 72 is impressive given how much she's going for it and how shaky her serve apparently is ... #WTAFinals
— Matt Trollope (@MattyAT) October 29, 2015

Sharapova took 3 games in a row to take her lead over Pennetta.

The former number 1 now takes over the lead instead. She's up 5-4, with Pennetta serving to stay in the match.

.@MariaSharapova breaks to level it at 4-4 ! #WTAFinals
— TODAY Sports (@tdysports) October 29, 2015

4-3 to Flavia Pennetta as Sharapova takes the game.

Down two games in the first set, 3 consecutive game points as Sharapova looks to hold serve. She's broken, and up 40-30.

Game point! And Sharapova holds to go 2-3 against Flavia Pennetta.

Pennetta is quickly consolidating her lead. She holds to take the score to 3-1 in the first set.

Sharapova holds with her first ace of the match to win the game. She's down 2-1 to Pennetta.

Pennetta, historically dominant against the Russian, closes out the first game in 3 minutes.

The Russian and the Italian have met a total of 5 times prior to today - in the 2 matches Pennetta has lost to Sharapova, she still took a set off the former World No. 1

Pennetta has beat Sharapova at the pair's last 3 meetings - most recently at Indian Wells this year.

The Italian, who won the US Open this year beating her compatriot and friend Roberta Vinci, announced her retirement at Flushing Meadows; this will be her last professional tennis tournament.

Pennetta comes in to the tournament on the back of a straight sets victory herself - over Radwanska.

Following Agnieszka Radwanska's straight sets victory over top seed Simona Halep earlier in the day, Sharapova moves to the semifinals of the tournament.