A teenage sensation at the start of his career, Borg experienced unprecedented stardom and consistent success that helped propel the rising popularity of tennis during the 1970s.

[6] At the age of 15, Borg represented Sweden in the 1972 Davis Cup and won his debut singles rubber in five sets against veteran Onny Parun of New Zealand.

Later that year, he won the Wimbledon junior singles title, recovering from a 5–2 deficit in the final set to overcome Britain's Buster Mottram.

Then in December, he won the Orange Bowl Junior Championship for boys 18 and under after a straight-sets victory in the final over Vitas Gerulaitis.

[7][8] Borg joined the professional circuit in 1973, and reached his first singles final in April at the Monte Carlo Open, which he lost to Ilie Năstase.

Borg was seeded sixth at his first Wimbledon Championships, in large part due to a boycott by the ATP, and reached the quarterfinal, where he was defeated in a five-set match by Roger Taylor.

[9][11] Borg made his only appearance at the Australian Open at the age of 17, and reached the third round, where he lost in straight sets to eventual finalist Phil Dent.

Just before his 18th birthday in June 1974, Borg won his first top-level singles title at the Italian Open, defeating defending champion and top-seeded Ilie Năstase in the final and becoming its youngest winner.

In early 1975, Borg defeated Rod Laver, then 36 years old, in a semifinal of the World Championship Tennis (WCT) finals in Dallas, Texas, in five sets.

[22][23] An out-of-court settlement was reached whereby Borg committed to play six or eight WCT events in 1978 which were then part of the Grand Prix circuit.

[24] Borg skipped the French Open in 1977 because he was under contract with WTT, but he repeated his Wimbledon triumph, although this time he was pushed much harder.

At the 1978 US Open, now held on hard courts in Flushing Meadow, New York, he lost the final in straight sets to Connors.

[42][43] In September, 1980 Borg reached the final of the U.S. Open for the third time, losing to John McEnroe in five sets in a match that cemented what had become the greatest contemporary rivalry, albeit short-lived, in men's tennis.

He defeated McEnroe in the final of the 1980 Stockholm Open, and faced him one more time that year, in the round-robin portion of the year-end Masters, actually played in January 1981.

Borg around that time felt that his desire to play was gone, despite McEnroe's desperate efforts to persuade him not to retire and continue their rivalry.

After that defeat, Borg walked off the court and out of the stadium before the ceremonies and press conference had begun, and headed straight for the airport.

Although he felt in good condition physically, he recognized that the relentless drive to win and defy tour organizers had begun to fade.

[43] Borg failed to win the US Open in nine tries, losing four finals, 1976 (the surface was clay that year) and 1978 to Jimmy Connors, and 1980 and 1981 to John McEnroe.

He did, however, play Monte Carlo again in March 1983, reaching the second round, and Stuttgart in July 1984, losing to Henri Leconte in both occasions.

[43][46] In 1991–1993, Borg attempted a comeback on the men's professional tennis tour, coached by Welsh karate expert Ron Thatcher.

He came closest to getting a win in what turned out to be his final tour match, falling to second seed Alexander Volkov 6–4, 3–6, 6–7(7–9) at the 1993 Kremlin Cup in Moscow.

[49] He hit the ball hard and high from the back of the court and brought it down with considerable topspin, which made his ground strokes very consistent.

[51] One of the factors that made Borg unique was his dominance on the grass courts of Wimbledon, where, since World War II, baseliners did not usually succeed.

Contrary to popular belief, however, this was not due to his exceptionally low resting heart rate, often reported to be near 35 beats per minute.

[63] Several players then called Borg in an attempt to make him reconsider, including Jimmy Connors and Andre Agassi, who volunteered to buy them to keep them together.

"[64] The conversation with McEnroe, paired with pleas from Connors and Agassi, eventually persuaded Borg to buy out the trophies from Bonhams for an undisclosed amount.

Perry's modern best behind Laver: "Borg, McEnroe, Connors, Hoad, Jack Kramer, John Newcombe, Ken Rosewall, Manuel Santana".

[72] In 1988, a panel consisting of Bud Collins, Cliff Drysdale, and Butch Buchholz ranked their top five male tennis players of all time.

"[76] From 22 to 24 September 2017, Borg was the victorious captain of Team Europe in the first-ever edition of the Laver Cup, held in Prague, Czech Republic.

Europe won the contest 15 points to 9, with Roger Federer achieving a narrow vital victory over Nick Kyrgios in the last match played.