Question: Johan Kriek's most memorable wins include victory over a tennis player who has been cited as one of the most what?

Context paragraphs:
1983 South African Open (tennis): The 1983 South African Open was a men's tennis tournament played on indoor hard courts in Johannesburg, South Africa that was part of the 1983 Volvo Grand Prix.  It was the 80th edition of the tournament and was held from 22 November through 27 November 1983.  Johan Kriek won the singles title.

Johan Kriek: Johan Kriek (born April 5, 1958) is a South African-American professional male tennis player and founder of the Global Water Foundation, a non-profit organization dedicated to delivering clean water to the world's neediest communities.  Kriek won two Australian Opens and reached the semifinals at the French Open and US Open, as well as the quarterfinals of Wimbledon.  He won 14 professional singles and 8 doubles titles, reaching a career-high singles ranking of World No. 7.  Kriek's most memorable wins include victories over Andre Agassi, Jimmy Connors, John McEnroe, Guillermo Vilas, Stefan Edberg, Michael Chang, Vitas Gerulaitis and Björn Borg.

1985 Alan King Tennis Classic: The 1985 Alan King Classic was a men's tennis tournament played on outdoor hard courts at Caesars Palace in Las Vegas, United States.  It was the 13th edition of the event and was part of the 1985 Nabisco Grand Prix circuit.  The tournament was held from April 29 through May 5, 1985.  Unseeded Johan Kriek won the singles title.

1984 Livingston Open: The 1984 Livingston Open was a men's tennis tournament played on outdoor hard courts that was part of the 1984 Volvo Grand Prix.  It was played at Newark Academy in Livingston, New Jersey in the United States from July 30 through August 6, 1984.  Johan Kriek won the singles title.

Global Water Foundation: The Global Water Foundation (GWF) is a non-profit organisation dedicated to delivering clean water and sanitation to the world's neediest communities.  Professional tennis player Johan Kriek founded the organisation in 2005 after attending meetings of the World Economic Forum in Cape Town, South Africa.  The goals of the GWF echo the Millennium Development Goals established at the United Nations' Millennium Summit in September 2000.

Lloyd Mondory: Lloyd Mondory (born 26 April 1982) is a French professional road bicycle racer who is currently suspended for four years for use of EPO.  The biggest results of his career include victory in the 2008 Grand Prix of Aargau Canton, stage wins in the Étoile de Bessèges, the Vuelta a Burgos and the Paris–Corrèze and second place in a stage of the 2008 Vuelta a España.

Jim Snyder (coach): James E. Snyder (June 29, 1919 – April 27, 1994) was head coach of the Ohio Bobcats men's basketball team for 26 years (1949–1974).  He amassed 20 winning seasons and led his teams to 7 NCAA Tournament appearances (1960, 1961, 1964, 1965, 1970, 1972, and 1974) and one National Invitation Tournament appearance (1969).  Snyder's teams compiled a 355-255 record, good for a .581 winning percentage.  He was also an Ohio graduate (Class of 1941), and was a football and basketball star as an undergraduate in the late 1930s and early 1940s.  One of his most memorable wins came against the University of Kentucky in the 1964 NCAA tournament, advancing the Ohio Bobcats to the Elite 8.  One interesting aspect of this game was that Ohio had an integrated team while Kentucky had one of its last all white teams.  Snyder was widely admired throughout the college basketball coaching fraternity as being a coach with great integrity and an engaging personality; he was often referred to as "Gentleman Jim."

1984 Bristol Open: The 1984 Bristol Open was a men's tennis tournament played on outdoor grass courts that was part of the 1984 Volvo Grand Prix.  It was played at Bristol in Great Britain from 18 to 25 June 1984.  It was the fifth edition of the tournament and the singles title was won by Johan Kriek.

1981 Monterrey WCT: The 1981 Monterrey WCT was a men's tennis tournament played on indoor carpet courts in Monterrey, Mexico.  The event was part of the WCT Tour which was incorporated into the 1981 Volvo Grand Prix circuit.  It was the third edition of the tournament and was held from January 19 through January 25, 1981.  Johan Kriek won the singles title.

Andre Agassi: Andre Kirk Agassi ( ; born April 29, 1970) is an American retired professional tennis player and former World No. 1 who was one of the sport's most dominant players from the early 1990s to the mid-2000s.  Generally considered by critics and fellow players to be one of the greatest tennis players of all time, Agassi has been called the greatest service returner in the history of the game.  Described by the BBC upon his retirement as "perhaps the biggest worldwide star in the sport's history", Agassi compiled performances that, along with his unorthodox apparel and attitude, saw him cited as one of the most charismatic players in history.  As a result, he is credited for helping to revive the popularity of tennis during the 1990s.

Supporting paragraphs: Johan Kriek Andre Agassi
Answer: charismatic players in history