The victory came through a 30th-minute own goal by Peter Crouch, who had scored the lone goal at Eastlands last May that took Tottenham into this season's Champions League at the expense of Man City yesterday night.
Securing one of England's four Champions League places was a key target for City's Abu Dhabi owners when they bought the club in 2008.
"We are employed to give performances and get results," City goalkeeper Joe Hart said. "Regardless of the money spent by the club, we are a team and we have shown that.
"If you watched the Champions League this season, Spurs have done brilliantly (reaching the quarterfinals) and it's a shame for them that they can't be there again as they brought something to it. But trips to Real Madrid, AC Milan and Inter Milan, what more can you ask for?"
An investment of more than USD 1 billion in players by Sheikh Mansour has also put City within one match of ending their 35-year title drought.
Stoke is up next in the FA Cup final on Saturday, and City striker Carlos Tevez is set to be fit for the match at Wembley Stadium after making a late substitute appearance having recovered from a hamstring injury.
"We now need a trophy and that is this Saturday," Hart said. "We got this tonight and we now need to give these fans a trophy."
Crouch's own goal came at the same end where he scored a year ago. City winger James Milner raced on to Adam Johnson's short pass and crossed low into a crowded penalty area, from which Crouch stuck out a foot and turned the ball into his own net.
The goal ensured City will play in the European Cup for the first time since 1968 - 24 years before the tournament was revamped into the Champions League.
If City finish fourth in the Premier League, the team will have to contest a playoff in August to reach the group stage.
With two rounds remaining, City is two points behind Arsenal and five adrift of Chelsea. Manchester United needs only one point to win the title.
"It doesn't mean we are in the Champions League. We would have to qualify, so why not get Arsenal?" City captain Vincent Kompany said. "We feel they may drop points and we think we can get six points."