Mourinho's decision making included hooking Zlatan Ibrahimovic as they went into the break 2-0 down.
He said: "Yeah, it was just tactical. [We changed to] only one central defender as we know that Burnley don't have normally the ball as they just play direct so we played one against one with Phil Jones.
"It is a risk and Jones accepted that and Nemanja Matic was there just to bring the ball from a totally free position, bringing lots of balls into midfield. Then, instead of more positional players like Zlatan Ibrahimovic, I decided to go with Henrikh Mkhitaryan, Jesse Lingard and Juan Mata with all three trying to play in these areas behind Lukaku.
"You can say we had some success and I still think there were so many balls in such important areas with lots of crosses, good and low crosses, but we didn't attack all these balls well. Also, normally, we were not lucky with rebounds so I'm happy with the effort, happy with the personality and happy with the feeling that we didn't lose but, of course, we lost two points."
Mourinho continued: "In the second half, it was impossible to concede a goal - impossible - because they didn't cross the midfield line, they didn't have two or three passes in a row. So, the second half was really ours - totally ours - but we still only scored two goals. I'm very happy with their character and part of that was also the way they played and tried to break down a very organised wall. I keep saying that to defend well is a quality and they defended very well. So also credit to Burnley to concede only two goals against such strong pressure."