The forward dominance they had shown at times in the first half really began to tell on the Marist eight.
Captain and No8 Johnie McFadzean capped off a period of sustained pressure and crashed over for the first of his two tries after four 5-metre scrums.
A Humberstone penalty and a 50-metre intercept try to Brown gave Carterton a 25-17 lead.
As Carterton upped the intensity, the Marist error rate and poor discipline escalated.
Referee Scott Andrew, who had penalised Marist for too much "chat" twice in the first half, sin-binned halfback Harry Warren for a similar offence.
Carterton took full advantage of the extra man, with first five Corey McFadzean dotting down behind the posts.
Marist were then briefly down to 13 when prop Ben Couch was red-carded for foul language. McFadzean capped off a strong game with a pushover try from a 5-metre scrum.
Others to impress for the winners were Brock Price, who was strong on defence and made several powerful runs, and winger Brown, who took full advantage of limited opportunities. It is hard to go past the Carterton tight five as the dominant factor in the game.
They completely dominated their Marist counterparts at scrum time, were assured on their own lineouts and gave their backs some quality ball to work with.
Carterton showed they can match it with the leading teams, but they remain 12 points adrift of Marist and will probably need other results to go their way to make the top four.
Greytown maintained their lead at the top of the points table but did not have everything their own way in their 22-3 win over East Coast.
The Coasters came out firing and took the game to Greytown, especially in the forwards, where they often had the home team on the back foot.
In the end, Greytown had too much class and were deserved winners.
Winger Nick Robertson was rewarded for some straight hard running with two tries, while utility forward Gareth Van Dalen, playing at flanker, must surely have enhanced his representative prospects with another strong performance.
The Eketahuna-Gladstone match at Eketahuna was a typically hard-fought battle.
Gladstone came away with the points, 21-5, but it was not until the second half that they gained any ascendancy.
Gladstone struggled in the first half and did not capitalise on their chances.
The introduction of lock Andrew McLean and flanker Richard Puddy from the bench gave Gladdy the impetus, and they took control of the second half.
Pioneer and Martinborough both scored two tries in their encounter, with Pioneer coming out on top 21-12.
No8 Lee Ewe and fullback Shayne Harmon crossed for tries for Pioneer, while former Auckland Under-19 representative, centre Sione Va'eno, was rewarded for some hard running with two tries.
Results:
Gladstone 21 (Jock Cameron, Richard Puddy, Dylan Lord-Bune tries, William Silvey 2 pens); Eketahuna 5 (Westly Lord try).
Greytown 22 (Nick Robertson (2), Gareth Van Dalen tries, Abe Southey 2 pens) East Coast 3 (Utah Walker pen).
Carterton 39 (Johnie McFadzean (2), Corey McFadzean, Danny Brown tries; Andy Humberstone try, 4 cons, 2 pens); Marist 17 (Malatai Malatai 2 tries, Keiran Te Whare 2 con, 1 pen).
Pioneer 21 (Lee Ewe, Shayne Harmon tries, Himiona Haira con, 3 pens; Joseph Thompson pen); Martinborough 12 (Sione Va'eno 2 tries, Tipi Haira con).
