United have now won just one of their last six Premier League games and could finish the day 11 points off the top of the table should Chelsea beat Burnley at Stamford Bridge.
Guardiola claimed earlier in the week his side's Champions League game against Club Brugge, which they won 4-1, was more important than the derby given there are 28 league games still to play.
Liverpool recorded their record victory at Old Trafford in a 5-0 thrashing two weeks ago to leave Solskjaer clinging onto his job as United boss.
Manchester City are second in Group A, one point behind Paris Saint-Germain after three games and two points clear of the Belgian side ahead of their game at the Etihad Stadium.
The visitors' celebrations after the match are alleged to have sparked a row involving several players and staff from both teams in the corridor.
Some City staff have claimed one of their physiotherapists was punched during the post-match ruck, but United have denied the same.
England's Football Association is investigating reports of a mass brawl that erupted in a corridor leading away from the Old Trafford tunnel.
Mourinho had claimed his side should have been awarded a late penalty, instead, Ander Herrera was booked for diving.
Pep Guardiola says Manchester City were always his first-choice club when he decided to come to the Premier League, despite Sir Alex Ferguson's attempt to lure him.
Snow is forecast to fall across northwest England in the hours leading up to kick-off and temperatures are set to drop to -1 degree Celsius.
Mourinho lit the blue touch paper in his pre-match press briefing by suggesting City's players went to ground too easily.
Leaders city are gunning for a record 14th successive league win, while United are seeking to notch up a 41st consecutive home match.
City's request to let the Amazon crew at the tunnel area and away dressing room was reportedly denied by their local rivals.
With so much at stake for both sides, the latest encounter in the 136-year-old rivalry promises to be one of the most explosive.
Guardiola claimed first blood, leading City to a 2-1 win at Old Trafford in September 2016, but both failed to win the League.