The visitors took the lead when Ross Wallace converted a Tyrone Mears cross after 28 minutes but Shane Long scored twice to take his season's tally to 10 and lift the Royals above Burnley in the npower Championship table.
"That win was hard earned but well deserved," he said. "They are a good side and played some really good stuff at times.
"Towards the end we got stronger and stronger and I thought we could have got the third so that I could relax, but we didn't.
"I think seven points from 12 is a successful Christmas period. Eight from 12 is Championship form."