Coleraine made it five wins from seven Premiership games by beating nine-man Portadown who began the day as leaders.
Mark Miskimmin executed a cool finish low into the bottom right-hand corner of the net in the second minute.
Michael Gault was shown a straight red card for a two-footed challenge on 30 and Ruairi Harkin tucked the ball under David Miskelly just short of the hour.
Substitute Darren Murray was sent-off for a challenge on Adam Mullan with three minutes remaining.
Miskimmin's strike from the left side of the area put the Bannsiders in control early on and the home side were really up against it when Gault was dismissed on the half hour.
Coleraine looked to extend their advantage but Miskelly tipped over an Ian Parkhill header, Harkin saw a 25-yard free-kick cannon off the bar and Mullan also went close.
Miskelly denied Harkin after the interval but was unable to do anything about the midfielder's next attempt as he latched onto a ball over the top and found the net from the left side of the six-yard area.
Portadown drop to fourth in the league table, with Coleraine moving up to seventh.
Coleraine manager Oran Kearney: "That was probably our best performance of the season - we created enough chances to win two or three games, and to keep a clean sheet was a bonus.
"This was a big test for us and our players came through it with flying colours."