It's a fight that has been five years in the making but on Saturday night, pound-for-pound king Floyd Mayweather Jr will finally face Filipino superstar Manny Pacquiao in a contest that has been billed as the biggest in the history of the sport.

As we build up to the showdown in Las Vegas, Sports Mole takes a look back at the last five matches involving Mayweather, who will be looking to extend his unbeaten record to 48 wins this weekend.

1. Miguel Cotto

After talks with Pacquiao hit a brick wall over how their fight purses should be split, Mayweather agreed to fight Puerto Rican Miguel Cotto in May 2012. Cotto had suffered a late stoppage defeat to Pacquiao in 2009 but after rebuilding his career at 154lbs by winning the WBA light-middleweight belt, he agreed to put his world title on the line as the American made the step up to the division for just the second time in his career.

The opening few rounds were secured by Mayweather, who controlled the bout with his movement and counter-punching in the middle of the ring, and by round six, he was comfortably ahead on the scorecards. Cotto responded during the middle part of the fight by pressuring his opponent, but despite still being a live contender in the match, there was always the feeling that Mayweather was in control, and in an entertaining final three minutes, a thundering uppercut effectively confirmed victory.

The result was left in the hands of the judges, but Mayweather deservedly emerged with scores of 118-110, 117-111 and 117-111 to record his 43rd successive win. After the fight, Mayweather credited Cotto by describing him as the toughest man that he had faced, but the performance only resulted in more calls for the Pacquiao fight to be made next.

2. Robert Guerrero

After spending two months in jail for domestic abuse, Mayweather returned to the ring in May 2013 against fellow American Robert Guerrero, who had amassed a record of 31 victories in 33 outings. The Californian southpaw was a three-weight world champion but he wasn't an opponent who captured the imagination of supporters, who expected a landslide victory for Mayweather in the defence of his WBC welterweight crown.

Guerrero began the contest well to build an early lead, but Mayweather soon adjusted to the challenger's style and it wasn't long before he was in full control of the fight. There were moments where Mayweather landed blows that would have stopped many of his previous opponents, but with the win effectively in the bag by the later rounds, he eased through to the end of the fight to pick up his 44th triumph.

All three judges scored the match 117-111 and Mayweather was able to move on to a more significant fight later in the year. At this point, any meeting with Pacquiao was deemed long gone, but Mayweather was still able to break records in his next outing.

3. Saul Alvarez

As he entered the final few fights of his career, there was a belief that Mayweather may look to protect his long-standing unbeaten record, but to the surprise of many, Mexican superstar Saul Alvarez was named as his next opponent for September 14. Despite being just 23 years of age, Alvarez had already competed in 43 professional matches and successfully defended his WBC light-middleweight title on six occasions.

With Alvarez regularly competing in a higher weight class, a catchweight of 152lbs was agreed for a fight that earned Mayweather a fee of $41.5m. This was before his share of 2.2m PPV buys, which was the second highest ever recorded after Mayweather's match with Oscar De La Hoya in 2007.

A competitive fight was expected, with many believing that Canelo's aggressive style would trouble Mayweather. However, Mayweather produced one of his best performances in years as he regularly picked off his opponent on both the front and back foot. Alvarez possessed the punch-power to change the course of the fight, but he struggled to get anywhere near Mayweather, who exposed the weaknesses in the South American's repertoire.

To the surprise of everyone watching at the MGM Grand and around the world, a score of 114-114 from CJ Ross was read out. It's a verdict that resulted in the retirement of the American judge, but the other two scores of 116-112 and 117-111 went in favour of Mayweather, although they still didn't do Mayweather's display much justice after such a masterclass.

4. Marcos Maidana

At the start of 2014, it soon emerged that Amir Khan and Marcos Maidana were the two fighters in line to meet Mayweather in May. It appeared as though Khan had the edge, but despite the Brit coming out on top in a poll, Mayweather opted to go up against Maidana. It was a bout that drew a mixed response, but after the Argentine's win over Adrien Broner, he was deemed to have done enough to gain his opportunity.

As expected, Maidana started at a fast pace and for the first time in recent memory, Mayweather looked uncomfortable. After four rounds, Maidana could lay claim to being at least two rounds ahead, but during the middle period of the fight, he began to slow down and that was all that Mayweather required to take over.

Ahead of the final two stanzas, Maidana required a knockout, and although he pushed hard, Mayweather proved too elusive to see out the rest of the match. Again, one judge ruled the bout as a draw, but the remaining two scored it 116-112 and 117-111, which was widely considered to be a fair assessment. However, despite the win, some questioned Mayweather's sharpness, suggesting that at the age of 37, father time was beginning to catch up with him.

5. Marcos Maidana II

With Khan unable to take a September date with Mayweather because of Ramadan, Mayweather was left with a lack of credible opponents for his second fight of the year. That left a second meeting with Maidana near the top of his shortlist and it was soon confirmed that the two would meet once again at the MGM Grand.

The rematch took a similar path to that of the first bout. Maidana began on the front foot and landed a thunderous shot at the end of the third that Mayweather took well. However, Mayweather soon showed that he was fighting within his comfort zone and Maidana resorted to trying to unsettle the champion by appearing to bite his glove in the eighth round and administering a low blow later in the fight.

Mayweather was momentarily rattled, but he regained his composure to combat his frustrated opponent and run out a convincing winner by scores of 116-111, 116-111 and 115-112 respectively. With a third contest out of the question, Mayweather would fight a new opponent in May 2015. Khan and WBA champion Keith Thurman were considered, but as soon as differences between the Mayweather and Pacquiao camps were resolved, only one fight made sense.