Many felt the long-awaited showdown at Manchester Arena on February 19 would, and perhaps should, be the the last dance for both men, who are now 35 and widely considered to be past their best.
Yet Khan and Brook have indicated they would like to carry on, with a rematch clause included in their fight agreement.
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The latter told The Star: "I’m feeling fantastic so who knows?
"I think I can go on and maybe should go on. I’m still sharp, I haven’t really had hard fights so I’m pretty fresh in that way. I’m going to talk with my family and think.”
Brook is back in Sheffield ahead of the bout, having spent Christmas and New Year training in Fuerteventura with his Ingle Gym stablemates.
“I feel very good,” he added.
“My body’s tired but that’s a good thing. My weight’s fantastic and my fitness is very, very good.
"Everything’s falling into place as it should be.”
That’s not to say it’s been plain sailing.
Like Khan, who is training in America, Brook sacrificed priceless time away from his family over the festive period and even missed his youngest daughter Vienna’s third birthday last month.
His second daughter, Estelle, turns seven on Saturday and eldest child Nevaeh is nine just four days before the fight, meaning Brook will not be able to celebrate with them as he would have liked.
"It’s very tough," he said of time spent away from his beloved daughters.
“The fans don’t see that, they just see you on February 19 in the ring. I’ve been on many training camps and even not been there (at home) when one of my daughters has learnt how to walk.
"I’ve missed plenty of birthdays, there’s a lot of that side people don’t see.”
The bad blood between both fighters has been on display throughout the build-up, however, yet the themes covered in a Daily Mail interview with Khan last week underline the pair’s similarities, even if they would be at pains to admit they have more in common than either would like.
Despite the consequences of their sacrifices, both are reluctant to walk away from the sport.
Asked about mistakes made and lessons learnt, Brook said he would advise his younger self to ‘live a better life’ and take the sport more seriously.
Khan eluded to the same errors.
So will February 19 provide any closure?
"The bottom line for me is about being happy,” said Brook. “That’s what I live for every day, just to be happy that day.
"This one is for myself. I've been a world champion, I have earned millions of pounds, been in with the biggest monsters – the best of the best – but this one is a grudge match.
"I can smile to myself saying I have done everything needed and wanted, everything I wanted to do in boxing.
"I have had a good career, after this Khan fight no-one can really argue with my career."
And what about when enough is enough?
"I can see myself going into managing fighters, maybe even training fighters."
Guess who else has started managing young fighters and now owns a boxing academy?