Question: Who was the higher ranked player of the same sport: Sun Tiantian or Björn Borg?

Context paragraphs:
1980 French Open – Men's Singles: Björn Borg was the two-time defending champion of the Men's Singles event at the French Open tennis tournament.  Seeded first he successfully defended his title at the 1980 French Open, defeating Vitas Gerulaitis 6–4, 6–1, 6–2 in the final to win his fifth French title after 1974, 1975, 1978 and 1979.  Borg went through the entire tournament, which featured 17 of the top 20 players, without dropping a set; this would not be achieved by a man again until Roger Federer at the 2007 Australian Open.

1973 ATP Buenos Aires – Singles: Guillermo Vilas defeated Björn Borg 3-6, 6-7, 6-4, 6-6 after Borg retired to win the 1973 ATP Buenos Aires singles competition.  Karl Meiler was the champion but did not defend his title.

Borg–McEnroe rivalry: The tennis players Björn Borg and John McEnroe met 14 times on the regular tour and 22 times in total, with their on-court rivalry highlighted by their contrasting temperaments and styles.  Borg was known for his cool and emotionless demeanor on court, while McEnroe was famed for his court-side tantrums.  Their rivalry extended between 1978 and 1981, with each player winning seven times against the other.  Because of their contrasting personalities, their rivalry was described as "Fire and Ice".

1978 French Open – Men's Singles: Björn Borg defeated defending champion Guillermo Vilas 6–1, 6–1, 6–3 in the final to win the Men's Singles tennis title at the 1978 French Open.  Borg did not lose a single set in the event.  The tournament also featured the first grand slam appearance of Ivan Lendl.

Björn Borg: Björn Rune Borg (] ; born 6 June 1956) is a Swedish former world No. 1 tennis player widely considered to be one of the greatest in the history of the sport.  Between 1974 and 1981 he became the first man in the Open Era to win 11 Grand Slam singles titles (six at the French Open and five consecutive at Wimbledon).  He also won three year-end championships and 15 Grand Prix Super Series titles.  Overall, he set numerous records that still stand.

1981 US Open – Men's Singles: John McEnroe was the two time defending champion and retained his title again, defeating Björn Borg 4–6, 6–2, 6–4, 6–3 in the final to win the Men's Singles tennis title at the 1981 US Open in a repeat of the previous years final, and which turned out to be Borg's final grand slam match.

Borg McEnroe: Borg McEnroe (Swedish: "Borg" ), also known as Borg vs McEnroe, is a 2017 English-language Swedish biographical sports drama film focusing on the famous rivalry between famous tennis players Björn Borg and John McEnroe at the 1980 Wimbledon Championships, culminating in their encounter in the men's singles final.  The film is directed by Janus Metz Pedersen, from a screenplay written by Ronnie Sandahl, and stars Sverrir Gudnason, Shia LaBeouf, Stellan Skarsgård, Tuva Novotny, and Robert Emms.  The film opened the 2017 Toronto International Film Festival.

Sun Tiantian: Sun Tiantian (; ; born 12 October 1981) is a Chinese former professional tennis player.

1980 U.S. Indoor National Championships: The 1980 U.S. National Indoor Championships was a men's tennis tournament played on indoor carpet courts at the Racquet Club of Memphis in Memphis, Tennessee in the United States.  The event was part of the Grand Prix circuit.  It was the 11th edition of the tournament in the open era and was held from February 25 through March 3, 1980.  First-seeded John McEnroe won the singles title and $40,000 first-prize money.  As a result of his title win McEnroe overtook Björn Borg as the ATP world no. 1 ranked player.

1974 U.S. Pro Tennis Championships: The 1974 U.S. Pro Tennis Championships was a men's tennis tournament played on outdoor green clay courts (Har-Tru) at the Longwood Cricket Club in Boston, USA.  It was classified as a Group AA category tournament and was part of the 1974 Grand Prix circuit.  It was the 47th edition of the tournament and was held from August 20 through August 26, 1974.  Fourth-seeded Björn Borg won the singles title and the accompanying $16,000 first prize money.  En route to the final Borg survived match points in both his quarterfinal match against Marty Riessen as well as his semifinal match against Jan Kodeš.  With his victory Borg became the youngest winner of the US Pro Championships at 18 years and two months, surpassing title-holder Jimmy Connors who did not defend his title but instead elected to play the Eastern Grass Court Championship in preparation for the US Open.  After the final, which was watched by a crowd of almost 6,000, Okker commented ""This was the first time I've played Björn Borg and at the moment I'm hoping it will be the last!"" .

Supporting paragraphs: Sun Tiantian Björn Borg
Answer: Björn Rune Borg