Ciftci grabbed the only goal of the game as the Tangerines came out on top in the Scottish Premiership at Tannadice.
McNamara said: "We have to give their keeper credit as he made a few good saves and it would have been more comfortable if we'd taken our chances.
"In the end, it took a world-class save from our keeper to make sure of the three points when the game should have been out of sight.
"Nadir actually had a couple of easier chances before his goal but I'm delighted he got another goal."
Youngster John Souttar featured for United against Killie after being linked with both Sunderland and QPR.
McNamara added: "There's been speculation about John Souttar.
"But there's been speculation every week since I came here in January and that's healthy. Nothing fazes him."