The former Nastic midfielder impressed in Hearts' CIS Cup defeat of Celtic and Frail remarked: "Celtic have good players in midfield, like Brown, Hartley, Donati, McGeady, so it's important that you are strong in there and we were.

"Marius Zaliukas gave us that bit of extra protection and Ruben did extremely well.

"He was comfortable on the ball, took it and passed it, put his foot in when necessary and won headers.

"I thought he was one of our best players."