The Belfast Giants fell to a surprise home defeat by the Hull Stingrays after blowing an early two-goal lead.
Goals in the first period of Saturday's Elite League encounter by Jeff Mason and Evan Cheverie looked to have put the title holders in command.
But the second-placed Giants conceded three without reply in a disastrous second period.
Will Frederick, Cory Tanaka, Omar Pacha and Eric Galbraith scored as Hull clinched an unexpected away victory.
The result represents a huge setback for the Giants who were hoping to eat into the four-point gap between them and the league leaders, Braehead Clan.
The Giants can get back to winning ways when they play bottom-placed Dundee Stars on the road on Sunday, face-off 18:30 GMT.
In other matches on Saturday, leaders Braehead ran out 5-1 winners over Fife, Dundee beat Edinburgh 2-1, Coventry won 5-4 in Cardiff and Nottingham won 4-1 away to Sheffield.