Martina Navratilova was the defending champion and won in the final 7–6, 6–2 against Raffaella Reggi.
Jack Sock (born September 24, 1992) is an American professional tennis player who is currently ranked world No. 21 in men's singles by the Association of Tennis Professionals (ATP).
 He is one of the top ranked American men in both singles and doubles on the ATP Tour.
 A former junior US Open champion, Sock's singles success is highlighted by 7 ATP finals, including three titles.
 His career best result came at the 2017 Indian Wells Masters, where he reached the semi-finals.
Jana Novotná and Catherine Suire were the defending champions but only Suire competed that year with Raffaella Reggi.
Raffaella Reggi (born 27 November 1965; ] ) is a former professional tennis player from Italy.
Nicole Provis and Elna Reinach won in the final 4–6, 6–4, 6–2 against Raffaella Reggi and Arantxa Sánchez Vicario.
Raffaella Reggi and Sergio Casal were the defending champions but lost in the semifinals to Martina Navratilova and Emilio Sánchez.
Raffaella Reggi was the defending champion but did not compete that year.
Terry Phelps and Raffaella Reggi were the defending champions but did not compete that year.
The Oslo Open was a women's professional tennis tournament held in Oslo, Norway.
 The event was part of the Women's Tennis Association (WTA) Tour and was played only once, in 1991.
 It was classed as a Tier V event, and it was competed on an indoor carpet surface.
 Catarina Lindqvist won the singles competition and Claudia Kohde-Kilsch and Silke Meier won the doubles; Raffaella Reggi finished runner-up in both events.
 There was a total prize money on offer of US$100,000.
Bettina Bunge and Katerina Maleeva were the defending champions but only Maleeva competed that year with Raffaella Reggi.

Question: What sport did Jack Sock and Raffaella Reggi play?
Answer: tennis