Spieth has won 11 times on the PGA Tour but is hoping to end a lengthy dry spell dating back over three years to the 2017 British Open.
Lahiri's rise up the leaderboard will inject the confidence he needed in his game following a lean spell in 2021, where he has missed five cuts in seven starts.
Rocket Mortgage Classic 2019: Anirban Lahiri falls 19 places from overnight position to Tied 52nd spot
Lahiri fell 19 places from his overnight position and is now at Tied 52nd spot at the Rocket Mortgage Classic
On a day when six players had at least a share of the lead, Mahan found a way to make it look like a comfortable win.