The hosts missed two clear chances to break the deadlock at the Liberty Stadium, with Alfie Mawson heading wide in the first half before Tammy Abraham saw an effort cleared off the line after rounding the goalkeeper.
However, it was a header from Newcastle skipper Jamaal Lascelles which proved to be the deciding goal, and Clement was left unhappy with his side's display.
"Although the margin of the defeat is small I am more disappointed with our performance. I am not satisfied with the way we played. There was expectation going in to the game but we were second best in combats, duels, first and second balls, tactics, in all aspects. I take responsibility for it. It is a performance I am not proud of," he told Sky Sports News.
"It is collective responsibility and I am at the head of that. We had a positive week going in to it and I didn't expect it. We had good training week and the meetings were good. The actual game, what I saw was nothing like I expected.
"We had a couple of good chances. On another day we could have got something out of it. They kept going but overall it wasn't good enough. You have to reflect honestly whatever the result, looking at what we could have done better. I think there are a lot of things we could have done better."
The defeat means that Clement has now lost back-to-back home league games for the first time in his managerial career.