The pair came through a tricky start making their debuts in our reserves' heavy loss against Southampton to play a key part in the draw at Palace last Tuesday.
Under-21 internationals for Iceland and Czech Republic respectively, Emil released David with the pass of the match at Selhurst Park, David was brought down and Lee Barnard scored from the penalty spot.
At the club for about a month now, they will be aiming to make a similar impact at Norwich on Wednesday night.
Coach Clive said: "They found it difficult to start with as you'd expect with new lads coming into a completely different environment, a new culture and the game against Southampton wasn't the ideal start for them.
"To their credit they've showed a lot of character in the way they've worked day in, day out, the way they've adapted to the requirements to play here and I was pleased with their performances at Palace.
"We saw Emil as a very strong, physical player with a lovely left foot that released David for the penalty against Palace.
"David showed glimpses of his speed, awareness and effort to get into dangerous areas.
"Their contribution was better and they acquitted themselves in a positive way.
"We need to give them time, we've all heard it before but they are young lads in a foreign country and it's not just football, they have to settle in to day to day life.
"They're decent lads with smiles on their faces and they've integrated well. It all bodes well for the future."
Clive Allen has been impressed with the character and progress of newcomers Emil Hallfredsson and David Limbersky.