Only 2 players outside our own half too.
That's the way Jose wants to play, though, and I'm personally fine with that, as long as we provide a counter threat.
As you can see, the two players in the oppositions half are the left winger (Sanchez) and the striker (Rashford), and this is what he has done throughout his managerial career, where he has given one winger less defensive duties, allowing them to be the attacking outlet and counter with the striker. It was Ronaldo and Higuain/Benzema at Real Madrid, Eto'o and Milito at Inter, Hazard and Costa at Chelsea and it seems Mourinho is going with Sanchez and Lukaku at United.
Difference is, he normally has a more defensive winger on the other side. Di Maria, Willian (Ramires for more solidity) Pandev (Chivu for more solidity).
Mata struggled with Chilwell against Leicester, and at one point, Mourinho had to put Rashford out there, as he couldn't match Chilwell with speed and strength. I guess this is why he wanted Willian, if rumours are to be believed. Perisic, who we were linked with last season, would have also been perfect for this role.
I think when Lingard is back, he'll come in for Mata. Not only does he work hard, but he has the ability to drive with the ball and provide a counter threat.