Cliftonville's Joe Gormley scored his fifth hat-trick of the season and broke his club record for the number of goals in a season in the win over Portadown.
Gormley netted an early penalty after keeper Billy Brennan had been sent-off for bringing down Johnny McMurray.
Ports striker Darren Murray took over in goals and was beaten when Gormley netted a header soon after half-time.
Gormley scored another penalty in the 75th minute and Martin Donnelly made it 4-0 for the deposed champions.
The win takes Tommy Breslin's men up to third in the Premiership table.
Portadown, who play Glentoran in the Irish Cup final on 2 May, fielded an understrength team at Solitude and one of the absentees was first choice keeper David Miskelly who was nursing an injury.
That gave former Lisburn Distillery keeper Brennan his chance.
However, Brennan's match lasted less than five minutes as he received a straight red card from referee Raymond Crangle for fouling young McMurray who had run on to a nice pass by James Knowles.
With no keeper on the bench, front man Murray took over in goals and he could do little as Gormley blasted the spot-kick into the roof of the net.
Cliftonville had chances to score more in the first half but were slack in front of goal.
They did score again early in the second as Tomas Cosgrove's cross from the right set up a simple header for Gormley.
That was his 38th of the term - the most ever scored by a Cliftonville player in one season.
But the record-breaker was not finished as he scored a 75th-minute penalty after Ross Redman had tripped Knowles.
Cosgrove set up Donnelly to stroke in the fourth near the end.