Manchester City manager Manuel Pellegrini claimed he could understand the frustration of New York City supporters after his victory in the fight for Frank

Lampard’s services. City are set to keep the former England midfielder until the end of the season after deferring his move to their sister club in the United States.

Lampard had been due to move to the new Major League Soccer outfit on January 1 but the Barclays Premier League champions announced on New Year’s Eve that his successful stint at the Etihad Stadium would be extended.

Fans of New York City, whose side join MLS in 2015, have expressed anger over the deal but Pellegrini claims it is in everyone’s best interests.

Pellegrini said: “Maybe all the New York fans, and I understand perfectly, they want to see Frank playing, because for the fans in New York to see Frank play is an amazing thing. “I hope that he will be there next year but I think that in this moment the best decision for him, for the club, for New York is to stay here with us.”

Lampard immediately showed why City were so keen to keep him by coming off the bench to score their winner in Thursday’s dramatic 3-2 home win over Sunderland.

Asked if he was impressed, Pellegrini said: “He has been a top player during his whole career, he has an important amount of goals. “I always say he is a very important player for us — that’s why we brought him here at the beginning of the season. It is very important also now that he will stay with us until the end of the season.”

The exact nature of Lampard’s arrangement with City is still unclear. It had been assumed that, after he was trumpeted as one of New York City’s marquee signings in the summer, that his spell in Manchester had been a loan. It is now apparent, however, that he was on a short-term full-time contract with City prior to the start of his New York contract beginning.

There is now uncertainty over when he will actually move to the US, with some pundits even suggesting he may not move at all.

When asked what the situation was at his Sunderland post-match press conference, Pellegrini was vague. He said: “You cannot have all different questions about Frank Lampard. He will stay now with us until the end of the season.”

New York City had used Lampard for much of their promotional activity ahead of their inaugural MLS season, which begins in March. It had been thought City would seek to keep Lampard until February to cover Yaya Toure’s absence for the African Cup of Nations but the new arrangement will deprive the American side of him until the summer.

A statement from NYCFC supporters group the Third Rail read: “On behalf of the Third Rail, we would like to publicly denounce City Football Group’s and Frank Lampard’s decision to extend his loan to Manchester City until the end of the Premier League season.

“Many fans, including our members, decided to support the team, committed to season tickets, and bought merchandise under the impression that Frank

Lampard would be playing for New York City Football Club, not Manchester City.

“Many of those fans are rightly outraged by this decision, and we support any course of action they take to voice their discontent over this decision.

“Our support for our ownership group has been unwavering until now, but this we cannot support.

“We reject out of hand any suggestion that NYCFC is in any way secondary to Manchester City FC, regardless of the source, and are disappointed that City Football Group would give such an appearance.

“The Third Rail will forever act as a voice for the fans of New York City Football Club.”