Super Munchkin Question - Rescue Kitten

[smilie23]

We were playing Super Munchkin last Friday and an interesting situation arose.

We were all at level 9 and Jason drew a Monster that he could beat easily. We tried to scupper his combat (otherwise he'd have won) and failed.
As a last ditch attempt I played "Rescue Kitten", a GUAL card with an alternative use:-

"... play it on a rival to interrupt his combat. He abandons the battle ... and he goes up a level."

Now the problem is the last part of the final sentence.
Does he gain a level, making him level 10, thus winning the game?
Or, does he NOT gain the level because he hasn't killed a Monster?

We discussed it, coz we could all see both sides of the arguement, but in the end I had to make a ruling (it's my copy of the game) that he DIDN'T gain the level because the card doesn't specifically say that "this CAN be the winning level", like 'Diving Intervention' or 'The Last Laugh' do.

Jason won the game on his next turn anyway, but we'd all be interested to know if my ruling was correct.