The Dutch centre forward has scored all five of Boro's goals so far this campaign, including the winner at Leeds United on Saturday afternoon.
"I'm delighted with Marvin, that's five goals in three games, and delighted for the boys," Mowbray told the club's official website.
"[Elland Road] is always a difficult place to go. The atmosphere they generate is a massive boost for the team.
"When the game loosened off with players getting sent off there was more space so we could utilise [Emnes'] pace and trickery."
This time last year the 23-year-old did not have a squad number at Middlesbrough and was sent on loan to Swansea City.