Crusaders moved up to second and ahead of Cliftonville on goal difference by winning Saturday's north Belfast derby.
Striker Jordan Owens scored the only goal with a powerful seventh-minute header from a Richard Clarke corner.
Cliftonville were adamant they should have had a late penalty but referee Ian McNabb decided Stephen Garret had not been impeded by Billy Joe Burns.
Paul Heatley could have got a second after that, but after rounding the keeper, his shot struck the post.
Penalty decision angers Reds boss
Cliftonville manager Tommy Breslin was disappointed with the referee's call after Burns challenged Garrett in the box.
"If that was not a foul, I have been watching the wrong game for years," he said.
"It was always going to be a tight game, and overall I don't think we worked their keeper Sean O'Neill enough.
"We were flat in the first half and were better in the second."
Verdict from the Crues camp
Crusaders skipper Colin Coates: "These games are important because you can gather momentum from them.
"We knew we had to perform to get the win and I think we deserved it.
"Big Jordan Owens is on fire up front and I am just glad he is in my team.
"If he keeps that up, and we can keep the back door closed, we will be all right."