Recapping Serena Williams' last four Grand Slam titles

Recapping Serena Williams' last four tournament titles in her quest for a calendar-year Grand Slam.

Serena Williams is three wins away from achieving a calendar-year Grand Slam for the first time since Steffi Graf did so in 1988. She would be only the sixth singles player to accomplish the feat if she can win the 2015 U.S. Open.

The world's top-ranked tennis player faces sister Venus on Monday night for the right to play in the U.S. Open semifinal.

Ahead of the pivotal match, here is a look back on the last four major titles that have the 21-time Grand Slam champion on the cusp of history.

2015 Wimbledon

In July, Williams defeated Spain's Garbine Muguruza, the world No. 20, 6–4, 6–4, to win her sixth Wimbledon and 21st Grand Slam title. The win gave Williams a 28-match winning streak at the majors, and set her up to achieve the first Calendar Grand Slam since 1988. 

2015 French Open

After falling behind 0–2 in the final set, Williams vanquished No.13 Lucie Šafářová 6–3, 6–7 (2), 6–2 in June to capture her third French Open title and 20th major overall. With the win, Williams also became the first woman since Jennifer Capriati in 2001 to win the Australian Open and French Open in the same year. She also became the third person to win 20 or more Slams, and the third person to win each Slam at least three times.

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2015 Australian Open

Williams defeated long-time rival and world No. 2 Maria Sharapova 6–3, 7–6 (5), at the Australian Open in January to win her 19th major title. Williams ended the match with 38 winners to Sharapova's 21, and had 18 aces and only 25 unforced errors. Williams' win gave her a sixth Australian Open title, and broke a tie with Chris Evert and Martina Navratilova for second-most Grand Slam singles titles in the Open Era.

2014 U.S. Open

Last September, Williams defeated No. 11 Caroline Wozniacki 6–3, 6–3 to win her third U.S. Open title in a row. The win marked her sixth U.S. Open and 18th overall Grand Slam title. Williams redeemed what was an otherwise disappointing Slam season, as she lost before the quarterfinals in three straight Slams before arriving in New York.

- Kayla Lombardo