Chawrasia began with a double bogey but had four birdies. He totalled one-under 287.
"This was a week I should have finished way higher. I left too many shots, allowed myself to get upset on the course and made mistakes with big numbers like a triple on third day and a double on final day," said Chawrasia.
"Those two holes alone meant five shots. At this level you cannot afford this.
"It has been a good experience, playing with the top players. I've learnt many things. To be honest, they know how to score. They adopt a different attitude each time they hit a bad shot. For me, I get angry and frustrated with myself. But for them, they don't care. They just forget about it and get on with their next shot. I've got to adopt the same mentality like them," he added.
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Rose's eight-shot comeback victory is a personal best for the Englishman and is also a World Golf Championships record.
Rose started the final day in tied-fourth spot and eight behind world number one Dustin Johnson, who was six clear of the nearest rival.
And Rose was still six behind Johnson after nine holes. Then he shot five-under 31 for the final nine while Johnson was three-over for the back nine. Rose at 14-under finished two ahead of Johnson, who along with Henrik Stenson (70), Brooks Koepka (71) was tied second at 12-under.
The Asian Tour Order of Merit leader Gavin Green of Malaysia signed off in tied 38th place after a final round 77.
It was Rose's second World Golf Championships title after his earlier victory at the 2012 WGC-Cadillac Championship. Johnson failed in his attempt to become the first player to win three World Golf Championships tournaments in a calendar year.