tennis, a bagel is when the set ends with a score of 6-0. An extremely rare type of bagel, where no point is lost, is called a  golden set. Most bagel sets occur in the early rounds of tennis tournaments where the favorites meet with lower ranked players such as a lucky loser or a wild card.
Statistics of the men's singles
Grand Slam tournaments from 2000 to 2016 are as follows: at Wimbledon (grass surface), 127 bagels were made; at French Open (clay surface), 267; at the US Open Tennis Championship (hard surface), 275, and at the Australian Open (hard surface), 238. . Björn Borg (five-time Wimbledon champion and six-time French Open champion) recorded 20 6-0 sets at the French Open, and only 5 at Wimbledon.
Grand Slam matches in the men's singles category are best of five sets. Thus, a kind of "inner double bagel" is possible, when a tennis player wins two consecutive 6-0 sets in a single match. The most recent occurrence is in
2018 when Gaël Monfils defeated Facundo Bagnis 7-6 (7-4), 3-6, 6-0, 6-0. 
In the 1970s, first round matches at the French Open and US Open were only best of three sets. There are 3 cases of a double bagel Grand Slam victory:
For women in Grand Slam tournaments, a double bagel result is possible as the matches are best of three sets. In the Open Era, not a single Grand Slam tournament match ended with a double bagel in 1968 and 2005.
The most double bagels were in the seasons of 1974 and 1993, when eight matches had a result of 6-0, 6-0.
The following players had at least five double-bagels in Grand Slam singles events:
Suzanne Lenglen (France), Margaret Court (Australia) - 14; Chris Evert (United States) - 13; Helen Wills Moody (USA) - 10; Steffi Graf (Germany) - 7; Kim Clijsters (Belgium), Mary Pierce (France) - 6 each; Monica Seles (Yugoslavia / USA), Maria Sharapova (Russia) - on 5.
Between No. 1 ranked players
There are seven cases when double-bagels ended with matches played by two tennis players who at different times were ranked No. 1 in the
ATP and WTA:
The triple bagel is very infrequent. In the Open Era, this has occurred five times in the men's singles Grand Slam tournaments so far:
In total, taking into account the preliminary rounds of
Davis Cup in the Open Era, there have been 17 triple-bagels. 
In Grand Slams
In the history of the Grand Slam tournaments in the men's single category, the largest number of 6-0 sets won is the following:
At individual majors the players with the most 6-0 sets are:
Australian Championship: 1. R. Federer - 17; 2.
Jack Crawford (Australia) - 16; 3. A. Agassi; N. Djokovic - 15 French Open: 1-3. B. Borg, G. Vilas, R. Nadal - 20 each; 4-5.
Jaroslav Drobný (Czechoslovakia /Egypt), R. Lacoste - 17 each. Wimbledon: 1. R. Emerson - 15; 2-3. J. Connors, B. Tilden - to 12.
US Championship: 1. J. Connors - 22; 2-3. I. Lendl, B. Tilden - 20 each.
Neale Fraser won at least 6-0 set in 16 Grand Slam tournaments in a row: starting with the 1957 Australian Championship and ending with the 1960 US championship.
In the women's singles, the largest number of 6-0 sets won:
Chris Evert (USA) - 106;
2. Margaret Court (Australia) - 89;
3. Martina Navratilova (Czechoslovakia / USA) - 72;
4. Steffi Graf (Germany) - 71;
5. Serena Williams (USA) - 64;
6. Helen Wills-Moody (USA) - 57;
7. Monica Seles (Yugoslavia / USA) - 54;
8. Maria Sharapova (Russia) - 49;
9. Arantxa Sánchez Vicario (Spain) - 46;
10. Gabriela Sabatini (Argentina) - 44.
In individual tournaments of the Grand Slam, the largest number of 6-0 sets won is:
Australian Championship: 1. M. Court - 25; 2. M. Sharapova - 16; 3. S. Williams - 14.
French Open: 1. C. Evert - 26; 2. A. Sanchez - 22; 3. G. Sabatini - 21.
Suzanne Lenglen (France), C. Evert - to 29; 3. M. Court - 25. US Championship: 1. C. Evert - 43; H. Wills-Moody - 31; 3. M. Court - 27.
Double Bagels 
Triple Bagels 
Trivia In 1948
Don Budge won the first match against George Hudson 6-0, 6-0, 6-0 at the US Professional Championship, and against Jerome Adler 6-0, 6-0, 6-1 in the second round. In 1969, in the
second round of Wimbledon, top seed Rod Laver began with the loss of the first two sets to the unseeded Indian Premjit Lall. However, the game ended in his favor with a score of 3-6, 4-6, 6-3, 6-0, 6-0. There are 4 cases in the history of tennis (two of which occurred in the French Open in
one tournament), when the winner of the match lost 2 bagel sets:  1935
(US Championship among professionals) Bill Tilden - Karel Ko?eluh 0-6, 6-1, 6-4, 0-6, 6-4  1962 (Tasmanian Championship)
Rod Laver - Neale Fraser 7-5, 0-6, 0-6, 6-1, 6-2 1969
(French Open) Stanley Matthews - Ilie Nastase 6-3, 0-6, 0-6, 6-4, 8-6 1969 (French Open) Dennis Ralston - Patricio Rodríguez 6-2, 6-4, 0-6, 0-6, 6-4 In 1981, in the first round of the US championship
Jimmy Connors, who in the mid-70s almost married Chris Evert, beat her then-husband John Lloyd with a score of 6-0, 6-0, 6-2. 
Suzanne Lenglen won 9 tournaments in which she did not lose a single game in all matches. 
Guillermo Vilas won 2 matches with a score of 6-0, 6-0 in 2 consecutive seasons ( 1980 and 1981). 
Björn Borg won 116 6-0 sets during his career  Two women's finals in the history of the Grand Slam tournaments have ended with a double-bagel:
 Swiss tennis player
Martina Hingis achieved her first Olympic bagel in singles in 1996, and the second in pairs twenty years later. Spanish tennis player Conchita Martínez scored the first double bagel against a player inside the top ten in Hamburg in 1995 when she defeated Magdalena Maleeva.
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