What was the name of the championship series Robert Seguso and Vasek Pospisil  were involved with?
Vasek Pospisil Vasek Pospisil (, ] ; born June 23, 1990) is a Canadian professional tennis player. He is the No. 3 male ranked player in Canada, after Milos Raonic and Denis Shapovalov. Pospisil has a career-high World singles ranking of 25, and No. 4 in doubles. As Canada's currently ranked No. 3 in singles and No. 3 in doubles, he is an important member of the Canada Davis Cup team. Along with partner Jack Sock, he won the 2014 Wimbledon Championships and the 2015 Indian Wells Masters men's doubles titles. He also reached the quarterfinals in singles at the 2015 Wimbledon Championships.
Champions Series (senior men's tennis tour) Since 2006, the Champions Series is a series of tennis tournaments designed for former champion members of the ATP Tour. The Champions Series consists of tournaments played in select markets where top players of the sport compete in one-night, four-player events with two one-set semifinal matches and a one-set championship match played in one evening.