QUIZ: Serena and Venus' rivalry across the years

For the 31st time on Thursday, Venus and Serena Williams faced each other as friends, sisters, and rivals.

The match took place in Lexington, Ky. at the Top Seed Open, a brand new WTA International tournament, and the rivalry is the first in the Open era to last four decades. Serena won the historic showdown in three sets, and would lose in the quarterfinals to Shelby Rogers.

While no one knows if this will be the last time the sisters play against each other (both of scheduled to appear in Cincinnati and the US Open), it's important to look back on their long history together.