AP, Manchester Alvaro Negredo and Edin Dzeko grabbed two goals each and Sergio Aguero scored on his return from injury as Manchester City swept to a 5-0 win over Blackburn in an FA Cup third-round replay on Wednesday. In taking its goal tally to 99 in all competitions already this season, City delivered another demonstration of its lethal firepower at Etihad Stadium to set up a fourth-round match at home to another second-tier team – Watford. City’s largely second-string lineup took a while to get going, with Negredo opening the scoring in first-half injury time, but the Premier League side was irrepressible after the break. Aguero scored within a minute of coming on as a 72nd-minute substitute following a month out with a calf injury, capping a perfect night for City manager Manuel Pellegrini. “You saw the difference between a (League) Championship and a Premier League team,” Blackburn manager Gary Bowyer said. “That was clinical … It’s phenomenal.” The 1-1 draw at Ewood Park on Jan. 4 was the only time City had failed to win in its last 10 matches and this replay will have been an irritation for Pellegrini, with his team’s fixture schedule clogged up due to its continued involvement in four competitions this season. For that reason, he fielded a shadow side except for Fernandinho in central midfield and the twin strikeforce of Dzeko and Negredo, who have been in great form during the eight-game absence of Aguero. Negredo, in particular, has been proved unstoppable this season and the Spain striker took his tally in five months in English football to 20 goals with a header that lit up an otherwise forgettable first half. Jesus Navas set clear Fernandinho down the right and the Brazilian’s cross to the back post was headed forcefully into the net by Negredo. The second half was a different story as City cut loose. Negredo scampered onto a curling, crossfield pass by substitute Aleksandar Kolarov to clip a finish high into the net in the 47th minute and Dzeko expertly turned in Navas’ cut-back to make it 3-0 in the 67th. Aguero, who has been out since Dec. 14, came on to a great reception and was soon celebrating a goal as he swiveled to shoot low into the net from Dzeko’s pass. Dzeko had the final say from another Navas cross in the 79th. City scored four or more goals in a game for the 11th time this season. It has 64 goals in 16 home matches.