The fallen Glasgow giants must try to pick themselves up for this weekend's vital tie with McNamara's United in front of what is likely to be a baying home support at Ibrox.
"Sunday's result puts more pressure on Rangers, no doubt about that," McNamara said. "They will be hurting and with it being their home ground that adds to the pressure.
"It will be up to us to get about them early and cause them problems. Is playing at Ibrox a negative now? I don't know, it depends. If they'd won on Sunday there would have been a feel-good factor.
"It wouldn't have defined their season but now there's a bit more pressure. We have a good support ourselves but it's their home crowd. It's their stadium.
"They will want to get the crowd behind them and help them, but at the same time we want to cause them problems and get at them."