Goals either side of half-time from Jeff Hendrick and Jamie Ward, who saw a third-minute penalty saved by Tom Heaton, and an injury-time strike from substitute Ben Davies saw Derby stroll to victory.
The margin would have been greater had it not been for Heaton, the woodwork and a contender for miss of the season from Conor Sammon.
After overcoming Leicester prior to the international break, the Rams recorded successive npower Championship wins for the first time since mid-December - when they beat Bristol City 2-0 at Ashton Gate.
Garner said: "Three goals and three points is the perfect way to start a busy run of fixtures and we'd have certainly taken that before kick-off.
"We've broken the 50-point barrier, which is massive, and with seven games to go now we're all looking forward to seeing what we can achieve in those games.
"I thought the lads were excellent from the word go. We could all sense that in training during the week. You could see everyone was refreshed after the break and we started the game like a house on fire, especially in the first 20 minutes.
"Our performance was excellent, we were on the front foot from the off and we put on a great display for our fans - that's 10 home wins now and we're making Pride Park a hard place to come to.
"The goals were all excellent in their own ways and a clean sheet is also a massive bonus for all the lads, especially for the boys at the back."