The New Zealand boxer had four straight wins to his name ahead of his bout with British fighter Derek Chisora in Manchester.
However, a lack-lustre victory over Junior Fa in February meant most pundits still felt Parker had more to prove in his quest to regain world champion status.
The 29-year-old admitted it wasn't his best work but said the fight wasn't much of a gauge for a clash with former title challenger and no-nonsense veteran Chisora.
"They're two totally different styles.
