The 1990 Cincinnati Open, was a tennis tournament played on outdoor hard courts. It was the 91st edition of the tournament and was part of the 1990 ATP Tour. It took place in Cincinnati, Ohio, United States from August 13 through August 20, 1990. Ken Flach and Robert Seguso were the defending champions, but lost in the second round to Sven Salumaa and Byron Talbot. Darren Cahill and Mark Kratzmann won in the final, 7–6, 6–2, against Neil Broad and Gary Muller.
John Fitzgerald and Anders Järryd were the defending champions but lost in the semifinals to Neil Broad and Gary Muller.
Ken Flach and Robert Seguso were the defending champions but lost in the semifinals to John Fitzgerald and Anders Järryd.
Defending champions Todd Woodbridge and Mark Woodforde defeated Grant Connell and Patrick Galbraith in a rematch of the previous year's final, 7–6(7–3), 6–3, 6–1 to win the gentlemen's doubles title at the 1994 Wimbledon Championships. It was the Woodies' second Wimbledon title and third major title overall.
The 1991 German Open was a tennis tournament played on outdoor clay courts and was part of the ATP Super 9 of the 1991 ATP Tour. It took place at the Rothenbaum Tennis Center in Hamburg, Germany, from May 6 through May 13, 1991. Sergio Casal and Emilio Sánchez won in the final against Cássio Motta and Danie Visser, 7–6, 7–6.
Ken Flach and Todd Witsken were the defending champions, but lost in the second round this year.
Rick Leach and Jim Pugh were the defending champions, but lost in the third round this year.
The men's doubles tournament at the 1992 US Open was held between August 31 and September 13, 1992, on the outdoor hard courts at the USTA National Tennis Center in New York City, United States. Jim Grabb and Richey Reneberg won the title, defeating Kelly Jones and Rick Leach in the final.
The men's doubles tournament at the 1989 US Open was held from August 28 to September 10, 1989, on the outdoor hard courts of the USTA National Tennis Center in New York City, United States. John McEnroe and Mark Woodforde won the title, defeating Ken Flach and Robert Seguso in the final.
The men's doubles tournament at the 1990 French Open was held from 28 May until 10 June 1990 on the outdoor clay courts at the Stade Roland Garros in Paris, France. Sergio Casal and Emilio Sánchez won the title, defeating Goran Ivanišević and Petr Korda in the final.
The men's doubles tournament at the 1991 US Open was held from August 26 to September 8, 1991, on the outdoor hard courts of the USTA National Tennis Center in New York City, United States. John Fitzgerald and Anders Järryd won the title, defeating Scott Davis and David Pate in the final.
The men's doubles event at the 1991 French Open tennis tournament was held from 27 May until 9 June 1991 on the outdoor clay courts at the Stade Roland Garros in Paris, France. John Fitzgerald and Anders Järryd won the title, defeating Goran Ivanišević and Petr Korda in the final.
Guy Forget and Yannick Noah were the defending champions, but none competed this year.
Grant Connell and Glenn Michibata were the defending champions, but lost in the semifinals to tournament runners-up Ken Flach and Robert Seguso.
Patrick Galbraith and Danie Visser were the defending champions, but competed this year with different partners. Galbraith teamed up with Grant Connell and lost in the semifinals to Jim Courier and Mark Knowles, while Visser teamed up with Laurie Warder and lost in the second round, also to Courier and Knowles.
Wally Masur and Jason Stoltenberg were the defending champions, but competed this year with different partners. Masur teamed up with Mark Kratzmann and lost in the semifinals to Jim Grabb and Richey Reneberg, while Stoltenberg teamed up with Todd Nelson and lost in quarterfinals to Pieter Aldrich and Danie Visser.
Tomáš Šmíd and Petr Korda were the defending champions, but Korda chose not to participate. Šmid partnered Karel Nováček, but lost in the first round to Ronnie Bathman and Rikard Bergh.
Paul Annacone and David Wheaton were the defending champions, but Wheaton chose not to participate. Annacone partnered with Doug Flach, but lost to Jim Grabb and Richey Reneberg in the first round.
Andre Agassi and Petr Korda were the defending champions, but Agassi chose not to participate. Korda played along Ivan Lendl, but lost in the first round to Neil Borwick and Simon Youl.
Ken Flach and Robert Seguso were the defending champions, but Robert Seguso chose not to participate. Flach partnered with Todd Witsken, but lost in the quarterfinals to Mark Woodforde and Todd Woodbridge.
Patrick Galbraith 
Danie Visser 
