McNamara's side took advantage of Ryan Stevenson's sending off to secure a 3-1 victory over Hearts thanks to goals from Russell, Willo Flood and Michael Gardyne.
He said: "I thought we were guilty of overplaying in the wrong areas at times. Sometimes we took too many touches on the ball which didn't help.
"But overall I'm happy with the result which means we've got two home wins.
"Rado Cierzniak was very commanding today but unfortunately he conceded that goal and there was nothing he could do about that. The only downside was not keeping a clean sheet.
"But I think we can look forward to playing Celtic away next week. Hopefully they will be a bit tired from playing Juventus during the week.
"We have the players to beat anyone on our day and that's what we have to think of going into any game.
"I also thought Willo Flood excellent as he was last week against Rangers.
"When the team is sitting in it's important they do that. We're in the top six now. We set targets where I think we should finish so we have to aim high."
The only thing I was disappointed today was not getting a clean sheet."