Winning streaks, finals streaks, Grand Slams, record since regaining No.1, since joining with Patrick Mouratoglou - all the Serena Williams stats you need are right here.
WTA Staff

NEW YORK, NY, USA - There are a lot of numbers floating around when someone's going for this much history, so we're putting them in one place - we'll also update this after every one of her matches this fortnight. So here you are - all the Serena Williams stats you need for the Australian Open!

(updated after her semifinal win at the Australian Open)

Serena & Grand Slams
~ Serena has the second-most Grand Slam titles in the Open Era with 21 (Graf 22)
~ Serena has the third-most Grand Slam titles all-time with 21 (Court 24, Graf 22)
~ Serena has the third-most Grand Slam match wins in Open Era with 291 (Navratilova 306, Evert 299)
~ Serena is trying to win her seventh Australian Open title (won it in 2003, 2005, 2007, 2009, 2010 and 2015); she already has the Open Era record for most Australian Open titles, male or female
~ This is Serena's 20th time being the No.1 seed at a Grand Slam (she's won 11 of the first 19)
~ Serena is 61-1 in Grand Slam first round matches (only loss: Razzano at 2012 French Open)

Serena & Finals
~ Serena is 21-4 in Grand Slam finals, the second-best winning percentage Open Era (Court was 11-1)
~ Serena has won her last eight Grand Slam finals (last loss: Stosur at 2011 US Open)
~ Serena has won her last 15 finals (last loss: Azarenka at 2013 Cincinnati)
~ Serena has won 30 of her last 32 finals (only losses: Azarenka at 2013 Doha & 2013 Cincinnati)

Serena & Age-Related Stats
~ Serena is the oldest woman to win a major in the Open Era (33y & 289d at 2015 Wimbledon)
~ Serena is the oldest No.1 in WTA history (set record when returned to No.1 on February 18, 2013)
~ Serena has the longest winning span between majors of any woman Open Era at 15 years and 10 months between 1999 US Open and 2015 Wimbledon (Evert, Navratilova and Graf had 12-year spans)
~ Serena has won eight majors since turning 30, the most after 30 by far in the Open Era (Court and Navratilova three each, King and Evert two each and Jones, Wade, Li and Pennetta one each)

Miscellaneous
~ Serena will spend her 153rd & 154th straight weeks at No.1 during the Australian Open fortnight (third-longest streak at No.1 in WTA history after Graf's 186 and Navratilova's 156)
~ Serena is spending her 276th & 277th career weeks at No.1 during the Australian Open fortnight (third-most weeks at No.1 in WTA history after Graf's 377 and Navratilova's 332)
~ Serena has the most career prize money in WTA history ($74.1M - next-most is Sharapova's $36.5M)
~ Serena has the fifth-most WTA titles in Open Era with 69 (after Navratilova, Evert, Graf, Court)

Before & After Patrick Mouratoglou
Serena joined forces with Patrick Mouratoglou after falling first round at the 2012 French Open, and the dynamic duo's numbers speak for themselves - here's a comparison of before and after Mouratoglou:

Pre-Patrick Mouratoglou
win-loss: 523-107 (.830)
WTA titles: 41
Grand Slam titles: 13 out of 47 (.277)
vs Top 10: 111-59 (.653)

Post-Patrick Mouratoglou
win-loss: 220-16 (.932)
WTA titles: 28
Grand Slam titles: 8 out of 14 (.571)
vs Top 10: 54-5 (.915)

Since Regaining World No.1
Since returning to the top spot on the WTA Rankings on February 18, 2013, Serena's been fantastic:
win-loss: 177-13
WTA titles: 22 of 29
Grand Slam titles: 6 of 11
vs Top 10: 39-3