Pippa Middleton: Barclays ATP World Tour Finals!

Pippa Middleton attends the Barclays ATP World Tour Finals held at the O2 Arena on Sunday (November 27) in London, England.

The 28-year-old younger sis of the Duchess of Cambridge watched the tennis match between Roger Federer and Jo-Wilfried Tsonga with her friends in the front row.

PHOTOS: Check out the latest pics of Pippa Middleton

Also at the match, Soccer star Cristiano Ronaldo.

Roger Federer claimed the record sixth ATP World Tour Finals title after winning in three sets with a 6-3, 6-7(8), and 6-3.

10+ pictures inside of Pippa Middleton and Cristiano Ronaldo at the ATP World Tour Finals…