Sam Deery, 28, of no fixed address, was sentenced to life imprisonment with a minimum term of 25 years.
Sebastian Niven, 18, of Sugden Road, Thames Ditton, was sentenced to life imprisonment with a minimum of 14 years.
Both were convicted at the Old Bailey in December and were jailed at the same court on Monday (February 19).
The jury heard that Farhad Khalili was attacked at around 7pm on December 15, 2021 as he walked along Surbiton Crescent, Kingston.
As he approached the junction of Anglesea Road, he was ambushed and attacked by Deery and Niven, who was 15-years-old at the time.
Farhad was stabbed multiple times before managing to stagger to Surbiton Road where he collapsed.
He died at the scene.
After looking at CCTV, police identified both Deery and Niven were identified attacking Farhad.
Deery had subsequently been detained after being wrongly identified as a suspect in a separate robbery that took place in nearby Portsmouth Road, Kingston, shortly before the attack on Farhad.
Niven fled on foot, but was arrested at his home address the next day.
While in custody, both Deery and Niven refused to answer any questions in their police interviews but were charged with murder based on the evidence against them.
Detective Inspector Jim Barry, from the Specialist Crime Command, said: “While Farhad and his assailants were known to each other it has never been established why they attacked him in such a violent manner.
“What is clear is that when Deery and Niven launched their attack, they did so with a ferocity and intent to cause Farhad significant harm.
“The actions of those on scene, including the officers who initially responded to the call, were commendable and helped us quickly identify and detain both suspects.
“The support and assistance from the local community was vital.
“This has enabled us to put those responsible for Farhad’s murder before the courts to face the consequences of their actions.
“I hope these sentences bring some small degree of comfort to Farhad’s family and friends who have been left to deal with the tragic outcome.”