Ivan Lendl ranked No . 1 in the 20th century .
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 .
Ivan Lendl