The Roosters led 18-0 at the half-time break and looked as though they would complete their first shutout of 2014 as they kept the Raiders scoreless for more than an hour in front of a home crowd of 11,815, but two late tries left Robinson disappointed that his side could not go on with their robust start.
"I thought we set it up in the first half," Robinson said.
"Canberra were completing high, doing a really good job in 'D', we actually got them on last tackles, so we had to work hard for it.
"We set it up in the first half; we came out in the second half and did a good job for 10-15 minutes there and then we fell off. We just weren't ruthless enough at the end to finish it off."
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"I was really happy with Pearcey tonight," he said.
"I thought he kicked well and kicked us into positions. He ran the ball at the right times and pushed the time around. I thought Pearcey was great tonight."
With a fifth win in six starts, the premiers move to fourth spot on the competition ladder. Robinson said his side was building toward reaching its potential with the halfway mark in the season approaching.
"We're sitting in a good position where we can get better," Robinson said.
"I think the perception's changed on where we should be at.
"We had the bad week against the Cowboys and we've had to work our way out of that. We just need to keep working hard. We're happy with where we're at.
"With all the stuff that happens, we're in a good position, but we need to keep working hard. We can't be satisfied with what we've done so far.
"That wasn't quite what we wanted tonight, that was a little bit short of that. Probably 25 minutes short of that and that's what we're focused on."
The Roosters will travel to Melbourne next week to take on a Storm side without Cooper Cronk and Billy Slater, before rounding out the crucial Origin period with home games against the struggling Knights and Sharks, plus a tough Round 16 clash with last year's grand finalists Manly and two byes.