Round knew in 2008 that he was the right fit as Moyes' sidekick after spells with Derby, Middlesbrough, England and Newcastle.
"David really impressed me from the first moment I met him," he recalled to the Manchester Evening News.
"I had done one year at Newcastle and I got a call off David to say he'd like to meet me because he needed a new assistant and he said I was his number one target.
"From the first minute we met I knew I was going to work for him. At that time I was at a bit of a crossroads in my career because I was starting to wonder whether it was time for me to be a manager.
"I had a couple of opportunities to have an interview for the manager's job. But after five minutes in David's company I knew I had to work with him. He sold me a vision and I was hooked.
"He is a terrific person with great honesty and integrity. He really knows his football stuff and he will succeed at United."
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