The United boss cannot wait to savour another fiery derby atmosphere so soon after he won his first City of Discovery clash since taking over in their recent Scottish Cup quarter-final victory at Dens Park.
McNamara knows there is plenty at stake for both clubs as his own side chase a top-six place, while bottom club Dundee continue their bid to avoid relegation.
But the former Celtic and Scotland international is urging his men not to let the occasion get the better of them.
He said: "It's another massive game.
"The atmosphere has been building up all week and we know what it means to so many people.
"But it's about keeping as calm as possible and trying to make sure we do the right things.
"There will be no shortage of motivation on our part, but we have to be composed and try to play the way we can."
McNamara praised his players for digging deep to win the last derby thanks to Gary Mackay-Steven's wonder strike, which secured their place in the Scottish Cup semi-final against Celtic.
But he knows that will have no bearing going into tomorrow's lunchtime clash at Tannadice.
He said: "It was obviously good to win the last one.
"But that won't mean anything as far as Sunday's game is concerned.
"This will be a totally different 90 minutes with other issues at stake.
"We can take confidence from that win but we will still have to work extremely hard to overcome what will be a very determined Dundee team."
United skipper Jon Daly is struggling with a groin injury, Brian McLean has a hamstring problem, while Johnny Russell and Gavin Gunning are long-term injury victims and Willo Flood and John Rankin are both suspended.
Recent recruit Rory Boulding looks set to make his derby debut after recently signing until the end of the season.