Five men have been jailed for killing 17-year-old Liam Hunt in Northampton on St Valentine's Day in 2017.
The judge said the killing was "only just short of an execution."
Jailing 18-year-old Kane Allaban-Hamilton for more than 14 years, the judge said the crime was "a stain on the town" and an example of "immature boys who think it's OK to carry knives".
Four other men were sentenced for manslaughter.
- Click to watch a report by ITV News Anglia's Sarah Byrd
The men tracked down Liam Hunt looking for revenge two days after a fight.
When they found him, he was punched, kicked and stabbed five times opposite a primary school in St George's Street in Northampton.
He sustained a fatal stab wound to his neck that was 7cm deep.
He then managed to stumble into this alleyway, where he collapsed. He died about an hour later in hospital.
18-year-old Kane Allaban-Hamilton was jailed for 14 years 9 months for Liam's murder.
21-year-old Aaron Joseph along with Lee Warren, Derice Wright and William Ransford, who are all 18, got sentences ranging from just over 3 years to 8 and a half years for manslaughter.
Two other teenagers were cleared of all charges.
Liam Hunt's family said his death has left a huge void in their lives.
In a statement they said: "Our boy was no angel, but we loved him more than words can express."