Boxing is a sport where being undefeated doesn't have to mean much. Many below-average fighters built impressive records while skipping on serious opponents. Heck, even Mickey Rourke is an undefeated pro! However, some would face anyone and finish their career without losses. This is a story about the top ten of them and their magnificent achievements that are often forgotten.

10. Sven Ottke

German Sven Ottke was always underappreciated, even as an amateur. As he started late, no one believed that he would be particularly successful. Still, these stories stopped once he became the European champion in 1991 and 1996. However, Ottke was the underdog again the following year, when aged 30, he finally turned pro.

Nonetheless, it took him only a year and 12 victories to challenge for the title, which he won against American Charles Brewer. After that, he defended it 21 times before retiring in 2004. Ottke's legacy could be better, as he rarely faced the best, refused to fight outside of Germany, and won quite a few controversial decisions. Plus, he's by far the least attractive boxer on our list, with only six wins by knockout. Well, he may be why boxing isn't among the most dangerous combat sports.

9. Michael Loewe

Like brothers Klitschko, many professional boxers from East Europe fought in Germany. Some of them even changed their names, including Romanian Mihai Leu. Leu, or Loewe, was a monster as an amateur, winning 190 of his 200 fights. Aged 22, he turned professional, and six years later, he won the world WBO Welterweight title.

Unfortunately, after a single defense the same year, he was forced to retire because of an injury. His record was an impressive 28-0, with only 10 KOs. However, he never fought top opponents, so he can't be high on our list. Despite his lack of fortune, Leu became a successful multi-sport athlete, excelling at the Romanian rally championship. In 2003 he won the title and kept racing well into his forties. Moreover, he got involved in politics.

8. László Papp

László Papp is a national hero in Hungary and is regarded as one of the best amateurs in history. Papp was a dominant athlete who won three Olympic golds and suffered only 12 losses in 319 fights! After the 1956 Melbourne Olympics, he became a professional, steadily building his record.

Unfortunately, the government of communist Hungary was never happy about his successes. Moreover, they saw him as an enemy, as the professional sport was banned in the country. In 1964, after amassing an impressive record of 27 wins and two draws, Papp was about to fight for the world title. However, he never got the permit to leave Hungary, which ended his career. This makes Papp unique on our list, as he's the only one who was never a champion.

7. Terry Marsh

We may have a pattern here, as Terry Marsh is another undefeated European pugilist who finished his career early. Also, like Papp and Leu, Marsh was great as an amateur, although not as successful. Turning pro in 1981, Englishman quickly improved his rankings with a string of victories. After six years, he finally fought for the world title, defeating American Joe Manley.

However, like Leu, Marsh defended his title only once, announcing before the bout he was retiring. While everyone was stunned by his decision, "The Fighting Fireman" later explained he had to stop because of epilepsy. Marsh finished his career with 26 wins and a single draw, never facing many great boxers of his era. While that's hardly his fault, it does affect his position on our list.

6. Edwin Valero

Edwin Valero was a true monster both inside and outside the ring. After a short but excellent amateur career (87-5), Venezuelan became a pro in 2002. Four years later, he broke the world record by winning his first 18 fights via KO, all in the first round! In 2006 he also grabbed the WBA super featherweight title before destroying everyone in the style of Mike Tyson until his last fight in February 2010.

Unfortunately, two months later, Valero was arrested on suspicion of murdering his wife. Only a day after, he was found dead in his cell from an apparent suicide. Known as El Inca, Valero died with a perfect score of 27 victories with 27 knockouts. We can only assume the level of greatness he could have achieved.

5. Joe Calzaghe

Joe Calzaghe is often mentioned as the best-ever super-middleweight boxer, and it's hard to argue against it. After winning three British amateur titles, he became a pro in 1993 at 21. Fighting mostly against journeyman and club fighters, Calzaghe built an impressive record before facing legendary Chris Eubank in 1997 for the WBO world title. After becoming a champion, he defended it successfully for the next decade!

Despite finishing with an impressive 46-0 record, Calzaghe's biggest achievement is that he fought against everyone. Besides Eubank, this list includes Jeff Lacy, Peter Manfredo Jr., Mikkel Kessler, Bernard Hopkins, and Roy Jones Jr.! Even though he won two fights on a split decision, most experts agree that he was a better rival in these bouts. Yet, most of them were past their prime.

4. Andre Ward

Unlike many American fighters, Andre Ward had a serious amateur career coming on top in 115 out of 120 matches. After winning numerous local titles, he won gold as a light heavyweight at the 2004 Olympics. The same year he turned pro, aged 21, and fought for his first title five years later. After upsetting Mikkel Kessler, Ward became the WBA super middleweight champion.

Throughout his career, Ward fought against the best in the super middleweight and the light heavyweight division. Some names he defeated included Edison Miranda, Arthur Abraham, Carl Froch, Chad Dawson, and Sergey Kovalev twice. His second fight against Kovalev in 2017 was also his last, as he quit with a perfect 32-0 score and 16 KOs. As for his relatively early retirement at age 34, Ward claimed he could no longer perform at the top level.

3. Rocky Marciano

For decades, Rocky Marciano had the best-ever record as a professional boxer, and it still stands true in the heavyweight division. However, despite that, you won't find anyone rating him as the greatest. Still, it's hard to blame Marciano for it since he had no great rivals. It says a lot that his most challenging fights were against Jersey Joe Walcott and Archie Moore, even though both were close to 40. 

Marciano's biggest strength was his power, winning all but six matches via KO. That power helped him overturn a few bouts he would have lost on points. It's pretty much forgotten that Rocky wanted to make a comeback four years after his retirement in 1955. Marciano even trained for a month to go for the world title once again but ultimately decided he was not ready for it.

2. Floyd Mayweather, Jr. 

Floyd Mayweather Jr. is a business genius, as we always felt that he earned most of the money from people paying to see him defeated. However, in his almost two-decade-long career, that never happened. Often portraying himself as arrogant, Mayweather Jr. once famously said, "Hey, everyone loses sometimes… Except me!" No other boxer in history built his career so much on being undefeated, which put so much pressure on him.

Being a defense master, Floyd wasn't particularly attractive in the later stages of his career, rarely winning by a knockout. However, no other fighter on our list defeated so many greats, including Diego Corrales, Jesús Chávez, José Luis Castillo, Arturo Gatti, Zab Judah, Oscar De La Hoya, Ricky Hatton, Juan Manuel Márquez, Shane Mosley, Miguel Cotto, Victor Ortiz or Manny Pacquiao! Love him or hate him, his 50-0 record and so many epic wins put him on top!  

1. Ricardo López

Mexico always had great fighters at the lower weight division, but Ricardo Lopez is their only champion who never suffered a defeat. Also, unlike every other fighter on this list, he completed his amateur career without a loss! Unable to find a real opponent, López turned pro at only 18, winning his first fight via knockout. After 26 consecutive victories, he earned WBC lineal mini flyweight title in 1990.

His reign of terror never stopped as he beat the best the division could offer, including future champions and many undefeated contenders. In 1998, he had his first and only drawn match, as the bout against Rosendo Álvarez was stopped after an accidental head clash. After winning a rematch, López moved to junior flyweight, where he won the title and defended it twice before retiring aged 35. His final record is hard to match, with 51 wins and a single draw.

Boxing for a decade or longer without suffering a defeat is tough, so all these fighters on our top ten list deserve praise. Being unbeaten is often a burden, but these men knew how to handle it and often became champions.

Who is your favorite undefeated boxer of all time? Do you think being undefeated is crucial to a fighter's legacy?

Cover photo: TopTens.fun archive