Englishman Holt had already produced breaks of 86 and 84 to keep world No 3 quiet and then ensured he would have no chance to get nervous on Table 2 by sealing the match for the loss of just one frame.
Williams showed glimpses of his best during the match but was disappointing overall against Holt, who is into the third round of the English Open where he has never previously won a main draw match.
The three-time world champion came into the Crawley tournament in good form, having reached the final of the China Championship only to be beaten 10-9 by Shaun Murphy despite recording a break of 143.
Ronnie O'Sullivan dispatches spectacular red
He then beat fellow Welshman Jamie Clarke in the first round of the English Open including another big break, this time reaching 142 in the sixth frame to complete a 4-2 victory over the 25-year-old.
But he was not at that level against Holt, failing to break 50 once in the clash and gifting his opponent the fourth frame by under-hitting the final ball.
Holt will now play Ricky Walden in the third round who will be keen to get back on the table after his second-round opponent Sam Craigie failed to turn up for their match.