Manchester City captain Ilkay Gundogan has set his sights on securing the treble after the club lifted their third consecutive Premier League title on Sunday.
The Gunners needed to win to delay City's title celebrations ahead of their home match against Chelsea on Sunday.
However, Taiwo Awoniyi's first-half goal proved enough to give Forest victory in front of a raucous home crowd, which secured their own top-flight status once again.
Guardiola's side will lift the Premier League trophy on Sunday for a third successive campaign, and a fifth time in six seasons, sealed with three matches to spare.