The world number one launched one 439 yards down the 16th at Firestone for the PGA Tour's longest drive in four years, watch it here...

WATCH: Dustin Johnson Hits Longest PGA Tour Drive Since 2013

World number one and defending WGC-Bridgestone Invitational winner Dustin Johnson hit the longest drive in four years today on the 16th hole at Firestone.

Disclaimer: The hole is downhill and regularly sees 400+ yard drives, but still, nobody has hit further than that for four years.

Dustin Johnson won the WGC-Bridgestone Invitational last year and has won three out of the last four WGC’s, including the Match Play and Mexico Championship earlier this year.

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