Champions Linfield recovered from their midweek defeat at Coleraine by thumping League Cup winners Crusaders.
Albert Watson headed in on 31 minutes and Philip Lowry quickly added a second with an assured finish in the box.
Early in the second half Crues defender Gareth McKeown was sent-off for hauling back Michael Carvill and Peter Thompson scored from the resulting penalty.
Late goals from substitute Daryl Fordyce and Billy Joe Burns capped an emphatic victory for the leaders.
The win keeps the Blues four points ahead of second-placed Portadown who won 2-0 at Lisburn Distillery.
The opening exchanges at Windsor Park were fairly cagey and the first decent dig at goal did not arrive until the 23rd minute when Lowry's shot was saved by O'Neill.
Then came the Linfield breakthrough, with defender Watson heading powerfully at the far post after Crues keeper Sean O'Neill had failed to cut out a Michael Carvill corner.
Seven minutes later Mark McAllister fed Lowry and the Limavady student shot in the second goal.
Things got worse for the Crues when defender McKeown got caught out by the alert Carvill and, when he pulled the Blues front man back, referee Raymond Crangle's red card was inevitable.
With the victory assured, Linfield took their foot off the gas for a spell and Crusaders almost hit back but Jordan Owens saw his powerful shot turned away by home keeper Alan Blayney.
In the 80th minute, Fordyce shot in from fellow sub Neil Dougan's cross and three minutes later a shot from outside the box by Billy Joe Burns deflected off Crusaders captain Colin Coates to beat keeper O'Neill.