It was about 12.20am when the roadside attack happened.
When the tourists did not comply Tierney dragged the 23-year-old male out of the van by his feet, got on top of him and punched him repeatedly until he was unconscious and then tried to choke him.
The 25-year-old female rushed to help her partner but also set upon and punched until her nose was broken.
Tierney ran off and the frightened couple took the chance to get in their van and drive off.
However, Tierney chased the fleeing couple.
It took them over one and a half hours before the couple finally reached safety after they arrived at Silverdale ambulance station.
Police met them at the ambulance station and they were both taken to North Shore Hospital.
The male was diagnosed with Post Traumatic Stress Disorder and is still having surgery to his nose that was broken in the attack. The woman also had to have surgery to her nose.
In a victim impact statement the male said he was still having flashbacks and nightmares as a result of the attack.
"I saw the hate and anger in his eyes that night and to me he is the human version of evil and that will never change."
The woman said in her statement she was still struggling with the aftermath of the attack and was having difficulties settling inot her job as a new lawyer.
"I really wish the assault never happened. It has turned my life upside down and for the worst.
"I really believe John would have died that night if I wasn't there to intervene."
When spoken to by police Tierney admitted what happened and explained that he didn't like foreigners and was drunk and bored.
The stress of the incident was too much for them to handle and they broke up shortly after leaving New Zealand.
Today defence lawyer Melissa Russell said at the time what may have sparked Tierney's behaviour was that he was taking unprescribed steroids to help with weightlifting and was also drinking alcohol.
She said since then he had stopped taking steroids and drinking and his attitude had improved.
In a pre sentence report the probation officer said that Tierney had a great attitude, a good job and was remorseful.
Judge Orchard said Tierney was a young man who clearly had the ability to rehabilitate himself and sending him to jail would serve no useful purpose.
"I do hope the Court does not see you again. Providedyou stay away from drink and drugs we won't see you again."
Police prosecutor Sergeant Stu Wilkes said Tierney had: ''let himself down, he's let his family down and he's let New Zealand down.''
