Kamaru Usman underlined his status as the UFC's pound-for-pound king but was made to dig deep by his fierce rival Colby Covington in Madison Square Garden. 

The 'Nigerian Nightmare' retained his welterweight title but failed to finish his challenger, who he conceded is a 'tough son of a b***h' as they buried the hatchet at the end of five gruelling rounds. 

Usman had the fans on their feet in the second when he knocked down Covington twice but the controversial American clung on for dear life and survived to see the third. 

To his credit, he then came on strong and the momentum began to shift before Usman regained some control behind his piston-like jab to see it out. 

Usman and Covington have held a genuine dislike of one another even before the champion broke the challenger's draw in their first fight two years ago. 

But there was a brief moment of respect when the curtain came down on their rematch as they embraced. 

Usman reflected: 'There was a lot of bad blood and I'm sure there will be some still but he is a tough son of a b****. When you share an octagon with someone tough you gain that respect. I can tell his technique and power has come up. I am the pound for pound best alive, we take our time, stay calculated.

'New York, thank you for coming out, I hope we put on a performance for you.' 

It was an enthralling five rounds but the flashpoint came in the second when Usman landed a chopping left hook to drop Covington to the mat and then followed it up with a longer one with the same result. 

The clock was Covington's friend and he managed to evade much further damage as the seconds ticked away. Usman showed his composure by refusing to chase what would have been a hugely satisfying finish and stayed risk free to take straightforward decision. 

In the co-main event, the judges were also called upon as Rose Namajunas retained her belt against Zhang Weili. 

Two of the judges scored it 48-47 but there were eyebrows raised at one 49-46 scorecard which was baffling. 

Having suffered a head kick KO defeat in their first fight, the Chinese star made a much better fist of it this time around, landing powerful shots and showing her strength advantage in the clinch. 

But Namajunas was too canny for her and dominated the final round to put the icing on the cake and seal the victory. 

The highlight of the night for many was the curtain-raiser between Justin Gaethje and Michael Chandler in their lightweight bout. 

On paper, this one was always likely to produce the fireworks and delivered everything it promised. In the end, it was a Fight of the Year contender with Gaethje the victor. 

Both men came out swinging for the fences and in the first round, the odds on them both hearing the final bell in the third would have been long. 

But somehow they both survived the slugfest and it was Gaethje who came up with the cleaner work, although his opponent deserves great credit for making it such a great spectacle. 

Gaethje is now adamant he is next in line for a title shot against the winner of Charles Oliveria's clash with Dustin Poirier in December. 

Islam Makhachev is riding an eight-fight win streak and is the other man in the frame for an opportunity so it will be interesting to see which direction the UFC decide to go.  

Earlier in the night, rising Irish star Ian Garry made a blistering start to his UFC career with a first round knockout win on debut to mark himself out as one to watch on what was a sensational night of action.  

 Scroll down through our live feed to see how the action unfolded...