Man City are set to seal the title tomorrow at home to West Ham, with United battling to finish in the Europa League places after a miserable season led by David Moyes.
Louis van Gaal is set to be named the new boss at Old Trafford next week and is set to overhaul the squad who have massively underachieved.
Sir Bobby is hoping that United become the top team in the city and get back to success after spending wisely in the summer.
“Next year I guarantee that we will be number one in Manchester. We like to be first and we will be first,” he said.
“We will have to buy a couple of players, which will happen.
“I am looking forward a lot to next year because Manchester United is not renowned for being second.”