MANCHESTER, England, April 4 (Reuters) - Erling Haaland scored a hat-trick as Manchester City crushed Liverpool 4-0 at the Etihad Stadium on Saturday to cruise into the FA Cup semi-finals and Chelsea also booked their spot in the last four with a 7-0 win over third-tier strugglers Port Vale. 

Champions Liverpool played well in the opening half-hour with Mohamed Salah wasting an early chance, but once Haaland had scored from the spot in the 37th minute after a foul on Nico O’Reilly their resistance crumbled.

Liverpool captain Virgil van Dijk conceded the penalty with a rash challenge, and there was little the Dutch defender could do as City played scintillating attacking football for the remainder of the game.

His blond hair swinging behind him in a ponytail, Haaland netted his second two minutes into first-half stoppage time with a well-placed header from an excellent Antoine Semenyo cross.

Semenyo got on the scoresheet himself five minutes after the break, latching on to a ball in behind from Rayan Cherki and chipping it beautifully past Giorgi Mamardashvili, and Haaland completed his treble with a shot off the underside of the crossbar in the 57th minute.

Liverpool's woes continued when Mohamed Salah, who is set to leave the club at the end of the season, capped off a poor performance by having his penalty saved by James Trafford, snuffing out any faint hopes Liverpool might have had of a comeback. 

LIVERPOOL FANS LEAVE EARLY

As the game turned into a victory parade, many Liverpool fans started heading for the exits, and City manager Pep Guardiola rang the changes, replacing Haaland with Omar Marmoush, the Norwegian striker receiving a standing ovation as he left the field. 

"First half, we struggled a bit, but then after around 30 minutes we kept going and in the end it's an amazing game. Another Wembley trip for us is amazing and important," he told broadcaster TNT. 

"I think (my form this season) has been a bit too much up and down, which is not good enough. I cannot keep on thinking about what I could have done differently or what didn't happen, or what happened. I have to think about the next game."

Chelsea had failed to score a goal in over 300 minutes of play in all competitions before Saturday, but went ahead in 64 seconds in their quarter-final against Port Vale when Jorrel Hato pounced on poor defending by the visitors.

Port Vale are bottom of England's third tier but had beaten Premier League Sunderland in the previous round.

A close-range strike by Joao Pedro and an own goal by Jordan Lawrence-Gabriel gave the eight-time FA Cup winners a 3-0 lead at halftime before headed goals by Tosin Adarabioyo and Andrey Santos, a poacher's finish by Estevao and an Alejandro Garnacho penalty wrapped up the win.

The 7-0 victory offered some relief to Chelsea coach Liam Rosenior after four defeats in a row in all competitions and ahead of next weekend's visit of Manchester City in the Premier League.

In the other quarter-finals, Southampton host Arsenal later on Saturday, with Leeds United travelling to West Ham United on Sunday. The semi-finals will take place at Wembley. 

(Reporting by Philip O'Connor and William Schomberg, editing by Ed Osmond)