It was far from a showpiece as, despite the fine afternoon conditions, both sides struggled to serve up a decent level of excitement.
A flat first half was only noteworthy for Fletcher's 14th-minute goal which Aussie keeper Paul Henderson will want to forget.
It was Tom Soares, Palace's best player, who made a positive run down the inside right channel before neatly dragging the ball back for the unmarked Fletcher.
The Palace skipper didn't get a good connection from 15 yards out, but the diving Henderson stumbled at first and then proceeded to nudge the ball over the line.
Palace should have doubled their lead shortly afterwards when Fletcher crossed low into the goalmouth only for James Scowcroft to completely miss the ball and then Clinton Morrison, a yard away at the far post, slide the ball wide.
Leicester were having a real off-day and Gabor Kiraly in the Palace goal was virtually redundant.
Iain Hume tried his best to get the Foxes moving but all too often he was feeding off scraps. The second half didn't get much better with passes going astray and long balls from both sides the order of the day.
But Palace's defence was rarely in trouble despite Leicester improving after the break.
Indeed the Foxes' first shot on target arrived on 70 minutes when Jarrett's shot was superbly saved by Kiraly. Central defender Gareth McAuley headed over a good chance following Porter's corner cross from the left but otherwise the home side were coping without too much bother.
Dougie Freedman lobbed over the bar for Palace before the Eagles finished the game off in stoppage time.
Skipper Patrick Kisnorbo was unlucky when the ball bounced awkwardly as he attempted to clear and struck his arm.
With Freedman and Morrison already subbed, Watson stepped up to take the penalty, Palace's first of the season, and made no mistake with a fierce shot which flew past Henderson and nestled in the left-hand corner of the net.