Going toe-to-toe with Alfadi, Marc easily outboxed the 27-year-old, knocking him to the canvas in the third and fourth round.
The judges scored the bout a unanimous 40-34 win in Leach’s favour.
Marc told SalfordOnline.com: “I wasn’t nervous at all before the fight, I was really hyped up for it.
“I got some great punches in early on – the main aim now is to improve my power so I can get an early stoppage.
“I’m looking at getting seven or eight fights set up over the next 18 months, after that I can look at going for a British title.”
Marc is steadily moving up the bill after the disappointment of controversially losing to Bobby Jenkinson on his debut back in November last year.
And a gruelling training regime under legendary coach Oliver Harrison has clearly added good decision making to his list of skills.
Marc came into the fight full of confidence after taking apart Middleborough’s Francis Croes in a 14 December bout in Bolton.
This lastest win means he jumps around 50 places up the BoxRec world rankings for his weight division.
Those in his corner now believe he is realising his considerable potential and believe within a couple of years he could be challenging for titles.
Oliver’s Gym co-owner Natalie Lewis told SalfordOnline.com: “Marc clearly dominated this fight from the opening bell and we are very pleased with his overall performance on the night.
“He has paid a lot of attention to what Oliver has told him and there is a definite improvement in his ability and attitude.
“The extra training that he put in has certainly paid off for him as you can tell by his style of boxing.”
“Marc will be fighting again soon and here at the gym we believe that he has the potential to go all the way.”