Boxing's volatile unpredictability means Anthony Joshua is taking nothing about a lucrative and potentially defining 2018 for granted.

Joshua moved to 20 stoppage wins from as many professional fights in Cardiff on Saturday, retaining his WBA and IBF heavyweight titles inside 10 rounds against the tough, brave but ultimately outgunned Carlos Takam.

The 28-year-old had blood gushing from his nose - "busted", not broken, he later revealed - in round two after a clash of heads with his stocky, bustling opponent but regrouped to floor Takam with a left hook in round four.

The Cameroon-born French fighter used all the veteran know-how of his 36 years to ensure Joshua was never entirely comfortable, but he was badly cut around both eyes by the time referee Phil Edwards called time after one minute and 34 second of the 10th.

Sporting a swollen nose – a badge of his trade at odds with his pin-up good looks – at the post-fight news conference, the London 2012 gold medallist made a convincing case that it rarely pays to peer too far ahead in the prizefighting game.

Indeed, Joshua does not need to look any further than his two prospective unification opponents - WBC champion Deontay Wilder and WBO king Joseph Parker - to find evidence of boxing mocking the best-laid plans.

Wilder is in action next weekend against Bermane Stiverne, the champion he dethroned in January 2015, after original opponent Luis Ortiz failed the third drug test of his career, while Parker's last defence was a forgettable points win over Hughie Fury in Manchester.

The challenger's cousin, Tyson Fury, was a furious and rotund presence in the ring afterwards when the verdict went Parker's way – the latest demonstration of how far the 29-year-old has fallen from the dizzying heights of his November 2015 win over Wladimir Klitschko, when a blockbusting domestic showdown with Joshua seemed inevitable.

"You know life; you never know tomorrow. I'm not worried about 2018. It is great, the possibilities that are going to come but we've got to get there first," Joshua said.

"The possibilities of 2018 are great. You never know the landscape, what's going on or what's going to happen in people's lifestyles. You just never know.

"So I'll enjoy this moment and what I have to come, and the possibilities of 2018 are bubbling quietly in the distance."

Joshua shrugged, "I'm easy," when asked who of Parker or Wilder he would prefer to face and deflected the question towards trainer Robert McCracken.

"I think both are winnable fights for Anthony," said McCracken, who helmed Carl Froch's stellar career.

"I'd say Parker and Wilder in that order because it will be a bigger fight with Wilder down the road than it is now."

Promoter Eddie Hearn is open to those prospective bouts taking place overseas, with Las Vegas calling for boxing's newest star attraction.

Hearn also conceded the 78,000 gathered at the Principality Stadium on Saturday, following the 90,000 at Wembley who watched Joshua's incredible win over Klitschko in April, make a compelling case to stay on home soil.

"To go to another country in a 4,000 [capacity] arena just for a little bit more money… AJ has always wanted to put on shows, inside and outside the ring, and there isn't a show like an Anthony Joshua show in world boxing," he said. "We don't really want to walk away from that."

Nevertheless, as his weekend wounds subside, Joshua knows his burgeoning superstar status depends upon an immovable bottom line.

"Without winning, no one would want to listen," he added. "Even though it's great, I know that everyone loves a winner and I can't afford to mess up."