Erling Haaland sent a warning to Manchester City's rivals after scoring five goals in their 6-2 FA Cup rout of Luton Town on Tuesday, saying he was back to his best and that "we're ready to attack."

Haaland had scored only three goals in seven appearances since making his comeback from a foot injury that ruled him out for more than a month between December and January.

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But the Norwegian striker looked back to his prolific peak at Kenilworth Road with a first-half hat trick and two more after the break as City cruised into the FA Cup quarterfinals.

In doing so, Haaland became the first topflight player to score five goals in an FA Cup match since George Best struck six for Manchester United against Northampton Town in 1970.

"I am getting back to my best," he told ITV afterward. "Finally I am feeling good. It's an amazing feeling. It's coming, we're coming. Exciting times ahead. We are ready to attack."

It was the second time Haaland has scored five goals in a game in just a season and a half with City, having done the same in the 7-0 rout of RB Leipzig in the Champions League last year. The 23-year-old now has 79 goals in 83 appearances for Manchester City in all competitions.

Haaland's first four goals against Luton came courtesy of assists from Kevin De Bruyne, who has also missed large parts of the season through injury.

"It's a pleasure playing with him," Haaland added. "I think we know what we both want from each other, we look at each other and it clicks well."

Haaland's performance and linkup play with De Bruyne will also fuel the belief City can emulate last season's treble of trophies when they won the Premier League title, FA Cup and Champions League.

"Erling was on fire and Kevin was perfect," Man City manager Pep Guardiola said. "The connection they have. Erling needs a player like Kevin and Kevin needs a player like Erling."

Mateo Kovacic also got on the scoresheet for holders City, who are unbeaten in 18 games in all competitions.

After -- by their standards -- a slow start to the season, Guardiola's side are now just a point behind Premier League leaders Liverpool and have one foot in the Champions League quarterfinals after a 3-1 win at FC Copenhagen in the first leg of their round-of-16 tie.

The second leg will take place March 6, after City face local rivals Manchester United on Sunday.

Information from the Associated Press and Reuters contributed to this report.