British club-record signing Di Maria was a second-half substitute in the landslide win, whilst Rojo remained on the bench for the friendly clash.
Ever Banega opened the scoring before Gonzalo Higuain, Nicolas Gaitan and Lionel Messi all bagged braces against Hong Kong in the Far East.
And United defender Rojo took to Instagram following the rout, joining Di Maria and his team-mates ahead of their flight back to the UK.
Rojo wrote: “Last stop before arriving in Manchester with the group @nicolasotamendi30 #Piri #fideo #fer and @agustinmarchesin1”
Rojo has made four Premier League appearances following a £16m switch to the Red Devils from Sporting Lisbon in the summer transfer window.
Meanwhile, Di Maria, who moved to United in a club-record £59.7m deal in August, has scored three goals and made three assists in five top-flight games.
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