Nottingham Panthers are odds-on to win the Challenge Cup for the fourth time in five seasons after a big win over league leaders Belfast Giants.
Former Giant Brandon Benedict got the only score of the first period and Brock Wilson and Matt Francis added to the Panthers tally in the second.
David-Alexandre Beauregard made it 4-0 and Jeff Mason pulled one back before David Clarke netted on the buzzer.
The second leg takes place at the National Ice Centre on 13 March.
The result left the home fans deflated as one of the three possible trophies the Giants are chasing appears to have gone.
The Elite League leaders found themselves behind when Benedict netted in the 11th minute from a pass by Sami Ryhanan.
Wilson tapped in on 11.57 in the second after Clarke's initial effort had been saved by netminder Stephen Murphy.
The Panthers scored again just 13 seconds later through Francis who pounced after Rhett Gordon had fired he puck back in.
Beauregard netted early in the third period but any notion that Mason's goal would spark a Giants revival disappeared when Clarke scored on 19.59.
"That was our worst performance of the season and it came at a horrible time," said Giants coach Doug Christiansen after the game.
"We made fundamental mistakes, but we have to learn from it and move on."