Portsmouth begin post-Adams era with win
Goals from defenders Glen Johnson and Hermann Hreidarsson eased the south coast club's relegation fears as they took three points for the first time since November.
With no other league matches taking place because of the FA Cup, Portsmouth, with Paul Hart in temporary charge, took advantage to move four points above the relegation zone.
Portsmouth goalkeeper David James was rarely troubled as he set a new record of 536 matches in the Premier League.
Johnson broke the deadlock with a brilliant finish 20 minutes from time before Hreidarsson's thumping header condemned City to a dismal defeat.
Big-spending City have won just once in 12 away league matches.