In February, City beat Chelsea on penalties to hoist the League Cup. On 11 May, they claimed their second successive Premier League title thanks to a 4-1 win at Brighton.
Though their points tally of 98 was less than last season's haul of 100, City's pursuit of that mark was largely ceremonial having already won the championship with half a dozen games to spare.
This season Liverpool were on their back until the last game.
With Jurgen Klopp's side ultimately vanquished, mid-table Watford, who lost twice to City during the Premier League campaign, impede the path to glory.
"We lost both games but I think we showed that we can beat them," said Watford manager Javi Garci. "We competed really well in both games in different moments. In the first game we lost 2-1 but we competed until the end and had chances at the end.
"In the second one we kept the result until the second half and then they scored from an offside position and the game changed."
City's last trip to Wembley for the FA Cup final ended in a surprise defeat against Wigan.
"I'm desperate, desperate, desperate to win the FA Cup," said City skipper Vincent Kompany, who played in the 2013 final. "You don't even know how much it's a priority."