Anthony Joshua has acknowledged that he will need to be on his "A game" in order to see off the challenge of Robert Helenius.

The two-time heavyweight world champion had been scheduled to face Dillian Whyte in a rematch of their December 2015 fight before his opponent failed a drug test.

Matchroom Sport have moved quickly to find a replacement in Helenius, who was confirmed as the opponent on Tuesday after only making a return to the ring last weekend after a 10-month absence.

With Helenius having been knocked out in one round by Deontay Wilder in October and having previously lost a wide points decision to Whyte, Joshua is naturally regarded as the heavy favourite to prevail at the O2 Arena in London.

However, the Finn has 32 wins from 36 outings on his record, his most notable coming against Adam Kownacki on two occasions when the Polish fighter was being pushed towards world title contention by US promoters.

Speaking at a press conference on Wednesday, Joshua admitted that he cannot afford to overlook Helenius, particularly having experience of losing to late stand-in Andy Ruiz when he made his United States debut in June 2019.

Joshua told reporters: "Late replacements aren't ideal, but this is the third time that it has happened.

"This is what happens, it is a long career that will bring up these type of obstacles and I have just got to get used to them. This is just another rock in my shoe on my way towards the top of the mountain."

"The principles remain the same in that I have to worry about myself. Helenius and me shared the ring together many years ago, and sparring is sparring as well, but we shared the ring together many years ago, but I have sparred so many different styles, competed with so many styles, but the objective remains the same, which is victory by any means. There is no overtime in boxing, so I need to be on my 'A' game and inflict pain to get the victory.

"It would be silly to underestimate Helenius. It is silly to underestimate anyone. So I have to take him deadly serious. But credit to him as well.

"He is coming to roll the dice, he wants to win. With other heavyweights, finances have been an issue, risk versus reward, but in reality, that isn't all that this is to him. He is here, he wants to win, so good luck to him."

Should Joshua come through with a win at the weekend, the expectation is that he will face Wilder in Saudi Arabia, most likely in the early weeks of 2024.