It was just the third victory in 18 MLS games for the Dynamo (10-15-4, 34 points), and the first under interim manager Davy Arnaud. Houston entered the match 0-6-1 since winning at Toronto FC on July 20. The triumph also ended an 0-3-1 stretch at home for the Dynamo.
A video review led to the cancellation of an Ethan Finlay goal in the 89th minute for Minnesota (13-10-6, 45 points), which failed to build on an impressive 2-0 victory at MLS-leading LAFC in its most recent match on Sept. 1.
The Loons also blew an opportunity to move into second place in the Western Conference while falling to 3-3-3 in their past nine league contests.
Houston got the first real chance of the night via Manotas in the seventh minute. However, his point-blank attempt from just outside of the box was saved by Minnesota keeper Vito Mannone.
Ramirez had a similar quality look in the 21st minute. Again, Mannone was there to bounce on the shot.
While Minnesota seemed to control a good portion of the tempo in the first half, the Dynamo struck in the 37th minute. DaMarcus Beasley delivered a brilliant grounded cross to Manotas, who drove the ball past Mannone for his 12th goal of the year.
Seven minutes later, Ramirez was paid back for his efforts. Taking advantage of a Minnesota turnover, Ramirez broke past the United defense and flipped the ball up and over Mannone for his fifth goal. Manotas was credited with an assist.
Minnesota United came out primed to get back into the match in the second half. Houston keeper Joe Willis made a massive arm save on Finlay's point-blank strike in the 59th minute. Dynamo defender Alejandro Fuenmayor made a sliding kick save in front of an open goal on a Finlay header in the 81st minute.
Finlay appeared to pull one back late for the Loons, but the video assistant referee ruled that the play was offside.