Montgomerie, McIlroy’s former Ryder Cup captain, believes the Northern Irishman should have played in an event in the three-week gap between Congressional and Sandwich.
But McIlroy, after practising at Royal St George’s, said: “Some people may have wondered why I chose to go from one major straight to another without anything in between and the answer is simple.
“Because of what happened at Congressional and the way it became such a big deal I wanted to get everything out of the way and sorted so that when I did start playing again I could just concentrate on golf.
“If I had gone to France (he pulled out of last week's French Open) I just would not have been able to practise or prepare properly. Every time I play I want to go out to win.”
By contrast world No2 Lee Westwood has opted to play in this week’s Scottish Open at its new Castle Stuart venue near Inverness and got off to a flying start by carding a first round 65.
The Englishman, who shares the lead with Mark Tullo of Chile on seven under, said: “The more pressure I’m under this week the better.
“It’s a nice way to start the next two weeks. I like playing the week before a major. I like having the pressure and making putts when you need to make them.”