There is nothing more exhilarating than watching two masterful contenders skillfully dance their way around the ring as they attempt to best each other in the "sweet science." So as Manny Pacquiao and Floyd Mayweather prepare to duke it out on Saturday, CNN takes a look at the best bouts in the history of boxing. JOHN GURZINSKI/AFP/Getty Images
Where better to start than one of the most famous clashes of all-time -- The "Thrilla in Manila." On October 1 1975, U.S. boxer Muhammad Ali took on his nemesis Joe Frazier for the third time in a brutal battle just outside the Philippine capital.
Amid the soaring temperatures, the pair slugged it out for the world heavyweight title. Often hailed as one of the greatest fights in sporting history, the pair known for their tumultuous rivalry went at each other with renewed fervor.
Finally after 14 rounds, Frazier's trainer called time despite "Smoking" Joe protesting from his corner. The 25,000-strong crowd erupted following the announcement with Ali himself quoted as saying: "I didn't realize he was so great. He's a real, real fighter." Rolls Press/Popperfoto/Getty Images
Perhaps few would have picked this boxing moment as a top bout in the lead up to the fight. But there is no doubt it has become something of a classic in the years since. Castillo started strong in his pursuit of the WBC lightweight title in Las Vegas on May 7, 2005.
Throughout the first nine rounds, the duo eagerly traded punches, during which time Corrales was knocked to the canvas twice. In an incredible feat of resurgence, the down-but-not-out yet thoroughly-bruised boxer landed a series of succinct shots that left Castillo hung out to dry on the ropes in the tenth round, after which the referee ended the fight. Nick Laham/Getty Images/file
Dubbed "The Showdown," the stakes were high going into the World Welterweight Championships in 1981. Sugar Ray Leonard was the WBC champion while Thomas Hearns remained undefeated going into the fight and owner of the WBA crown.
The two landed punch after punch for 12 rounds by which point Leonard's trainer Angelo Dundee wailed to his fighter: "You're blowing it, son!"
"Sugar" found renewed vigor in his legendary trainer's desperate calls erupting with a force Hearns could not have expected and threw him against the ropes. It was enough as Leonard continued to repeatedly pummel Hearns in the 14th before the referee ended the night's festivities at Caesars Palace. Getty Images / Staff/file
Both light of foot, these two Mexican fighters went head-to-head on February, 19, 2000 at the Mandalay Bay Hotel in Las Vegas. Morales started the bout strong landing a series of unrelenting punches on his countryman.
But things took a turn in the fifth when Barrera managed to summon some strength from within to offer up an incredible combination of punches leaving Morales shaken and wobbling against the ropes.
Later in the 12th, Barrera served up a beating and the first knockdown of Morales' career, who was forced to retreat to the ropes in an attempt to stay upright. The outcome was eventually determined by a 12th-round split decision in favor of Morales with the crowd criticizing the result. JOHN GURZINSKI/AFP/Getty Images/file
The first from the epic trilogy between Ward and Gatti took place on May 18, 2002.
The pair traded savage blows from the bell. The mutual beat down didn't abate for nine rounds, by which point Ward had a fair few cuts to his face. But he'd managed to knock Gatti, who was suffering from an increasingly swollen left eye, to the floor and won by majority decision in the 10th.
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It was to be the first time an Argentine boxer would vie for the World Heavyweight title. Unfortunately it was not the night for Luis Angel Firpo, aka the "Wild Bull" of Pampa.
Dempsey's title defense before a crowd of 80,000 at New York's Polo Grounds was a short but perhaps not too dignified affair. Firpo was knocked to the canvas seven times... in the first round. Dempsey was announced winner in the second round by KO after dropping Firpo 11 times in total. The bout lasted just three minutes and 57 seconds. Topical Press/Hulton Archive/Getty Images/file
A brutal battle billed as "Thunder vs. Lightning" -- this clash is arguably one of the most contentious bouts in boxing history with an dramatic ending like no other.
Chavez threw countless punches to no avail as Taylor's speed allowed him to delicately evade each attempt. But when he did connect, Taylor certainly felt it.
Exhausted by the fierce pace, Taylor was wiped out by the 12th, even falling as he tried to deliver a blow. Chavez seized his moment and unleashed with one minute of boxing prowess on his weakened challenger, who eventually succumbed, dropping to the floor.
Here's where it gets murky. Fight ref Richard Steel asked if Taylor could continue. Some argue Taylor nodded an affirmative response. But with no verbal answer, Steel declared Chavez winner by TKO with a staggering two seconds left on the clock. Ken Levine/llsport/Getty Images
Hearns makes another appearance in this best bouts round up -- this time for his fight against Marvin "Marvelous" Hagler and what many consider the "best opening round ever."
Hagler, who had a history of slow starts, unleashed an aggressive slew of jabs and uppercuts from the off. "Hitman" Hearns returning with his own brutal blows. By the end of the first round, Hagler's face was covered in blood from a particularly unrelenting series of punches from Hearns. But he remained determined.
The pace continued in the second but the pair couldn't do this all night. After eight minutes, Hagler took down the "Hitman" for good with a third-round KO winning the WBC middleweight title, WBA world middleweight title and the IBF middleweight title. The Ring Magazine/Getty Images
Billy Conn had given up his light heavyweight crown to take on Joe Louis on a summer's night in 1941 at the Polo Grounds. Conn also known as "The Pittsburgh Kid" started strong and began to outbox the heavy favorite and title defender, Joe Louis.
The pair continued to exchange punches with Conn up by two by the 12th. However things took a turn in the 13th when "The Pittsburgh Kid" got cocky. Thinking he could end things, he went for the KO but in the process exposed his defence. An exhausted Louis took advantage and fought back with a powerful right a minute into the round. The titleholder finished things a few moments later with a series of well-placed blows and Conn went down. Joseph Costa/NY Daily News Archive/Getty Image