It means a first defeat of the season for Monk's men, who slip down to third place in the early league standings.
"We played some good stuff in the first half," FourFourTwo quotes the 35-year-old as saying. "We should have really come in with the lead. [We're] disappointed to have conceded that goal just before half-time.
"I think in the second half you saw the power and the quality that Chelsea have and we couldn't quite contain them. It's disappointing, but the players gave what I asked of them.
"Their whole team is packed with world-class players who can cause damage to you at any time and that's obviously why they pay the money that they pay to have those players here. I can promise you they [the players] won't be disheartened. We have to improve, of course we do, but in terms of where we're at in this league, you have to put it in perspective as well."
Next up for Swansea is a home match against Southampton.