El Ouazghari is a late replacement for Brunet Zamora, who was stopped from boarding his flight to London by airport officials, and Mitchell is expecting the Spaniard to be aggressive in their bout at the ExCel Arena.
The 29-year-old told Sky Sports News: "I have trained really hard. I have had a change of opponent, which I was told about late on Wednesday night but those things happen. I am lucky that I am still on the bill, thanks to Eddie Hearn who got me a good opponent.
"This kid that I have got now, I remember him fighting John Murray a couple of years back. He is very tough, awkward, throws some big shots, is a bit of a puncher and it looks like it will be a good fight.
"I am looking to take him out and do a demolition job on Saturday night."
A win for Mitchell would take him a step closer to securing a shot at the IBF title in 2014.