Patrick McKendry: Andy Ruiz Junior safest option for Joseph Parker

According to trainer Kevin Barry, the now 24-year-old Parker dominated Ruiz Jr in all six rounds of their third of three sparring sessions in 2013.

Andy Ruiz Junior or Wladimir Klitschko? Joseph Parker's safest route to the WBO world heavyweight boxing title is clearly Ruiz, but the New Zealander also has a good chance against Klitschko, known as Dr Steelhammer, the former undisputed champion in danger of going rusty.

Parker, the WBO No1 who highlighted his credentials for a world title fight when stopping the 2.01m Alexander Dimitrenko with ease in Manukau on Saturday, has sparred with Mexican Ruiz Jr and Klitschko, so is aware of their strengths and weaknesses.

According to trainer Kevin Barry, the now 24-year-old Parker dominated Ruiz Jr in all six rounds of their third of three sparring sessions in 2013.

And last year Parker trained with Klitschko in Miami before the Ukrainian's defence against Bryant Jennings at New York's Madison Squire Garden, which he won by unanimous decision.

It is believed that Parker more than held his own against Klitschko in the ring, to the point where the Kiwi was landing so many blows Klitschko was marked under both eyes, including a cut under one. Parker's speed, in particular, had him in difficulty.

More than a year on, Klitschko has fought only once since the Jennings bout - his unanimous decision defeat by Tyson Fury in Germany in November last year - while Parker has been in the ring eight times.

Klitschko was bullied by Fury, while Parker's growth has been significant. In May, he became the IBF mandatory challenger with his points victory over Carlos Takam.

It was a fight Parker clearly won over 12 rounds, yet he was under-par physically due to overtraining and criticised in some quarters for his lack of head movement.

Against Dimitrenko, the head movement was significantly better and so was his power. There was pressure on Parker to provide a statement of intent and he delivered, knocking down his opponent three times in the first two rounds and finishing him in the third.

Ruiz Jr, a 27-year-old undefeated over 29 professional fights, has freakish hand speed and timing but would give away 5cm in height to Parker and hasn't face the quality of opponent that Parker has. Klitschko has lost only four times in 68 professional fights and is 5cm taller than Parker, but turns 41 next March. He is a dedicated athlete and trainer, but what toll will that inactivity over the past 11 months take on a fighter ?

Parker is in the perfect position to take advantage of the opportunities that will be provided if and when Tyson Fury is stripped of his WBO and WBA titles.

As No1 with the organisation, Parker must fight either Klitschko or Ruiz Jr for the title.

If it's Ruiz Jr, the fight will be in Auckland on December 10.

It's unlikely to halt the speculation in Europe that IBF champion Anthony Joshua could fight Klitschko for the WBO title in December.

But if negotiations between Klitschko and Joshua fail, which is a distinct possibility given the money and logistics involved, Parker could instead fight Klitschko, probably in Germany.

The organisation's rules are clear. If it's not Ruiz Jr, it will be Klitschko.

And Parker showed against Dimitrenko, he is ready for either.

WBO heavyweight rankings

Champion: Tyson Fury.
1. Joseph Parker.
2. Wladimir Klitschko.
3. Andy Ruiz Jr.

IBF heavyweight rankings

Champion: Anthony Joshua.
1. Joseph Parker.
2. Kubrat Pulev.
3. David Haye.