On March 3, 1980, John McEnroe overtook Bjorn Borg to become the ATP Tour's top-ranked singles player for the first time. In just his fourth year on the pro circuit, McEnroe, 21, caught his rival on the heels of winning the 1979 U.S. Open, the first of his seven Grand Slam titles.
"There was suddenly more pressure, everywhere," McEnroe told the ATP last year of taking over the top spot, which he owned in doubles at the time, too. "I got goose bumps thinking that I was ranked ahead of Bjorn Borg and Jimmy Connors. It was inspiring to hit that mark, but it made me want to improve myself."
McEnroe held the No. 1 ranking for only three weeks before Borg regained it, as the two battled it out during a memorable season. Borg outlasted McEnroe 1-6, 7-5, 6-3, 6-7 (16), 8-6 in the Wimbledon final, one of the greatest matches of all time. Their epic -- and, yes, this is one of the appropriate times to use that word -- 34-point fourth-set tiebreaker is worth another watch:
McEnroe got revenge with a 7-6 (4), 6-1, 6-7 (5), 5-7, 6-4 victory in the U.S. Open final, his only win in four matchups that year against the Swede, who finished the season No. 1.
They met in the final of Wimbledon and the U.S. Open again in 1981, too. McEnroe won both to even the series at 7-7 -- and they'd never play again. The latter loss left Borg without a title in 10 U.S. Open appearances and effectively ended his career at age 25.
McEnroe used 1980 as a springboard to a dominant run. He wound up as the year-end No. 1 from 1981-84, one of only four players (along with Jimmy Connors, Pete Sampras and Roger Federer) to finish on top in four consecutive years. He held the No. 1 ranking for a total of 170 weeks, fifth all time. (h/t Randy Walker)