"They were doing quite well until we came along," Reweti said.
"It was a very good game, a very exciting game.
"We had to work for our points, it went right to the wire."
Boxon took only a two-man bench to Levin, where it rained all match.
They were held up over Levin's tryline three times, with Reweti disputing one referee call that they knocked the ball on.
Leading 10-4 at the break, Boxon had to deal with another home team comeback for their second straight match but unlike in Linton a fortnight ago they held on.
It was the usual suspects who brought in the points as representative fullback/winger Pentuakau Turia-Bennett scored the first try, then barnstorming representative centre Che Barlow added the second from another individual effort.
Koro got the third four-pointer.
Whanganui Boxon will take on Kia Ora in their last round robin game in Palmerston North on Saturday.