The first incident took place in Baljeet Nagar area in central Delhi last night when victim Rajkumar and his two friends were allegedly attacked by four youths near his house.
Kumar had an altercation with one of the accused a few minutes before the incident. The accused then called three of his friends and they attacked him with knife and sticks, police said.
While Kumar's two friends managed to save themselves, he received four stab wounds in the abdomen which proved fatal.
In the second incident, a 27-year-old auto-rickshaw driver was stabbed by unidentified assailants in the BRT corridor in South Delhi last night.
Victim Avneesh Kumar was lying in a pool of blood on the road when passersby saw him. He was taken to hospital where doctors declared him dead.
Police said prima facie it seemed that he was killed over personal enmity, but they were investigating the case from all angles.