The Welsh club took an unexpected lead through a John Terry own goal in the 11th minute, making a brighter start than their hosts at Stamford Bridge.
However, the imperious Diego Costa pulled Chelsea level just before the interval and added another two to his tally in the second half.
Debutant Loic Remy added a fourth after coming on for Costa, with Jonjo Shelvey's late effort proving to be a mere consolation.
The result ended Swansea's 100 per cent start to the Premier League season, but Monk was quick to see the positives.
"We played some good stuff in the first half," he said. "We should have really come in with the lead. [We're] disappointed to have conceded that goal just before half-time.
"We maybe should have added one or two - we had some good chances - but 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."
