Ebou Adams' stoppage-time winner broke the hearts of League newcomers Sutton as Forest Green started life under new boss Rob Edwards with a 2-1 victory.
Sutton started brightly enough in their first shot at League football in their 123-year history.
Omar Bugiel was a threat against his former club and only a last-ditch foul from Jordan Moore-Taylor snuffed out his buccaneering run on goal.
However, it was Rovers who nosed ahead on the half-hour - Matty Stevens placing a towering header across goalkeeper Dean Bouzanis from Nicky Cadden's arrowed cross.
Sutton grabbed the initiative after the break and Bugiel scored his side's first EFL goal as he pounced on statuesque Rovers defending to stab the ball beyond Luke McGee.
Cadden saw a deflected strike kiss the top of the crossbar as Forest Green upped the tempo.
With Sutton looking to bag their first point, Adams had the last word, glancing home a free-kick from Regan Hendry in the first minute of time added on.