Despite having 15 attempts on goal, Palace were unable to beat Guglielmo Vicario in the Tottenham goal, with Archie Gray's header not long before half-time proving the only goal of the game.
Hughes was one of several players in red and blue who went close to finding the net, but ultimately the crucial goal eluded Palace.
When asked what was lacking, he answered: "I'd probably say being ruthless in front of goal. We had our chances throughout the game.
"But we just couldn't put the ball in the back of the net.
"I think the manner of the defeat, we can be proud of the performance as a whole, compared to the Leeds game last week where, as the manager said after, we deserved to lose.
"But ultimately performance alone doesn't get you the points and that's why we are frustrated tonight."