But they eventually succumbed 48-20 to the holders at Pottington Road.
Most pleasing for the new club, though, was that they had a full-strength squad for the first time.
Keith Fillingham, the Raiders spokesman, said: "It was encouraging to gather a 21-man squad for the game, although with many of them being new faces, it will take time to become a cohesive unit.
"In the phases where we played to a game-plan, we were easily the equals of the Eagles, but only time spent together both playing and training will make us a solid team in both attack and defence."
The Raiders went 10-0 up with tries by Nick Casanova and Will Topps, who finished an 80-metre break by debutant Sam Wollacott.
The Eagles drew level with tries by Graham Price and Paul Morgan before Dan Cuthbertson powered over to put them ahead.
Ben Parry broke through the Eagles line, only to be thwarted by a forward pass just short of the line.
And the visitors extended their lead to 20-10 before the break with another Morgan try.
Sean Lovett and Brad Perkins added tries for the Eagles after half time, but their lead was pegged back to ten points by Parry and Dom Heap crossing.
However, the visitors sealed their place in the semi-finals with three converted tries in the last ten minutes from Darren Bowden and Mark Wathes (two)
The North Devon Raiders go to Torquay on Saturday to face Devon Sharks, the leaders of the Co-operative Rugby League Conference south west division.