The two 18-year-olds now have to wait until July 30 to be sentenced, with one facing a mandatory life sentence for murder and the other to be jailed for manslaughter.
Ruben Moreno, of Aldfield Way, Longley and Isaac Ramsey, of Andover Street, Burngreave, were both 17 when violence on Horninglow Road, Firth Park, last August.
The teenagers had both arrived at a house party armed with knives and a 24-year-old man was slashed across his chest and abdomen at the gathering, triggering a chain of events which ultimately resulted in the fatal stabbing of 35-year-old Marcus Ramsay, who was stabbed in his heart by Monero.
Sheffield Crown Court heard that Marcus was trying to prevent the Monero and Ramsey from chasing his brother when he was knifed.
Senior investigating officer, DCI Mark Oughton said: “This case yet again lays bare the horrors brought by knife crime.
“Marcus Ramsay was an innocent bystander, whose gut instinct was to intervene and protect his brother from two teenagers he could clearly see were armed. Marcus was doing his very best to diffuse a dangerous situation. He wasn’t involved in the evening’s violence; he was trying to put a stop to it.”
Moreno and Ramsey were captured on CCTV fleeing as Marcus lay dying after the knife attack.
They then went on the run for a number of weeks.
DCI Oughton continued: “It is undeniable that Moreno and Ramsey arriving with knives dramatically, and unnecessarily, escalated this situation. Both friends had a propensity for carrying weapons, and I am pleased that justice has been served today. The streets of South Yorkshire will be safer without them.”
Moreno, who was found guilty of murder, had already pleaded guilty to the possession of a bladed article.
Ramsey, who was found guilty of manslaughter, was also convicted of wounding with intent after an assault in Gower Street, Burngreave, on December 20, 2019.
Following a car crash, Ramsey stabbed the other driver, who was unarmed, four times.
The 33-year-old required hospital treatment for his injuries, which included a collapsed lung.