Claim: Ivan Lendl was ranked No. 1.

Ivan Lendl -LRB- -LSB- ˈɪvan ˈlɛndl̩ -RSB- ; born March 7 , 1960 -RRB- is a former world No. 1 professional tennis player and is currently coaching current world No. 1 Andy Murray , alongside Jamie Delgado . Originally from Czechoslovakia , he became a United States citizen in 1992 . He was one of the game 's most dominant players in the 1980s and remained a top competitor into the early 1990s . He has been described as one of the greatest tennis players of all time . Lendl 's game relied particularly on strength and heavy topspin from the baseline and helped usher in the modern era of `` power tennis '' .   Lendl captured eight Grand Slam singles titles . He competed in 19 Grand Slam singles finals , a record surpassed by Roger Federer in 2009 , Rafael Nadal in 2014 and Novak Djokovic in 2016 . He reached at least one Grand Slam final for 11 consecutive years , a record shared with Pete Sampras , with the male primacy of eight consecutive finals in a Grand Slam tournament -LRB- a record shared with Bill Tilden at the US Open -RRB- . Before the formation of the ATP , Lendl reached a record 12 year-end championships -LRB- equalled by John McEnroe -RRB- . He won two WCT Finals titles and five Masters Grand Prix titles , with the record of nine consecutive finals . He also won a record 22 Grand Prix Super Series titles -LRB- 1980 -- 89 -RRB- , the precursors to the current ATP Masters 1000 .   Lendl first attained the world No. 1 ranking on February 28 , 1983 and bolstered his claim to the top spot when he defeated John McEnroe in the 1984 French Open final . For much of the next five years , until August 1990 , Lendl was the top-ranked player -LRB- with a break from September 1988 to January 1989 when Mats Wilander was at the top -RRB- . He finished four years ranked as the world 's top player -LRB- 1985 -- 1987 and 1989 -RRB- and was ranked No. 1 for a total of 270 weeks and set a new record previously held by Jimmy Connors , since broken by Pete Sampras and Roger Federer . He is one of three male players in the Open Era -LRB- with Connors and Federer -RRB- to win more than 1,000 tennis singles matches -LRB- 1,071 -RRB- . Lendl has won 94 singles titles , second only in the Open Era to Connors ' 109 titles . Lendl has been runner-up in a record 11 Grand Slam finals .