Donna Sheridan’s show-stopper “The Winner Takes It All” had special meaning at the August 23 performance of Mamma Mia!: The world’s top two tennis players, Novak Djokovic and Rafael Nadal were in the audience! In town for the U.S. Open, the friendly rivals decided to relax at a Broadway musical, then made their way backstage at the Winter Garden Theatre to meet the very excited cast. Click on to see the Serbian and Spanish-born tennis champs vamp it up with the Lycra-clad stars of Mamma Mia!