It was when Manchester United defeated Arsenal in a seismic FA Cup semifinal in April 1999 that Sir Alex Ferguson's team started to believe they could achieve the unthinkable by doing the Treble. Manchester City's rampant 4-1 victory against the same opponents on Wednesday has now done the same for Pep Guardiola's side.

The Treble is on. City are 11 games from greatness and from erasing the word "unique" from United's claim to be the only English club to win the Premier League, FA Cup and Champions League in the same season.

United have the chance to halt City's march and ensure that Old Trafford remains the only English ground to house those three trophies at the same time, by beating their neighbours in the FA Cup final on June 3.

But City are now displaying such ominous form that the Treble has gone from being impossible to improbable to seemingly inevitable. Arsenal could have de-railed City's charge completely by winning at the Etihad, but they never came close.

By beating Mikel Arteta's team -- who have led the Premier League table for 28 matchdays compared to City's four -- City are now in full control of the title race. They remain in second position, but are only two points behind the Gunners having played two games fewer. Win both matches and they will be four points clear, but they will even claim top spot with two draws due to their vastly superior goal difference.

"The next three games are really, really important," Guardiola said. "Game by game and we will see what happens. The reality today, it's sounds naive, but we are behind Arsenal on the league table."

All true, but the league title is now City's to lose. Yet winning the Premier League for a third successive season is now just one strand of a bigger objective. It is all about the Treble. Even if City win the league and the club's first Champions League, this season will go down as a story of what might have been if they don't win all three competitions they are still alive in.