Manchester City showed no mercy on beleaguered West Ham by romping to a 3-0 victory in the second leg of their League Cup semifinal on Tuesday, completing a 9-0 aggregate thrashing.

Alvaro Negredo scored twice and Sergio Aguero added the other goal to ensure City will contest its first League Cup final since 1976, against either Sunderland or fierce rival Manchester United at Wembley Stadium on March 2.

Having grabbed a hat trick in City’s 6-0 win in the first leg two weeks ago, Negredo ensured there would be no miracle turnaround by heading in the opening goal at Upton Park after less than three minutes.

Aguero clipped home a deft finish in the 24th for his third goal in as many matches since returning from a calf injury and Negredo powered through some weak defending to wrap up the scoring in the 59th. It took City’s goal tally for the season in all competitions to 106 in 35 games.

Most neutrals will likely be hoping for an all-Manchester final, but Sunderland leads the other semifinal 2-1 after the first leg. The return match is at Old Trafford on Wednesday.

British bookmakers were offering odds of 500-1 that West Ham would complete an inconceivable turnaround. Many in the media dubbed it “Mission Impossible.”

And even though City fielded a weakened lineup, the visitors maintained a professional, positive attitude to the second leg and had far too much class for West Ham, which has endured a miserable season and is marooned in the Premier League’s relegation zone.

It’s the biggest aggregate margin of victory in a League Cup semifinal.

“It was important the way we reached the final, winning all our games,” Pellegrini said.

Pellegrini started with his first-choice strikeforce and Negredo opened the scoring after just three minutes, emphatically heading in a cross from 18-year-old Portuguese winger Marcos Lopes.

Aguero, who was making his first start since returning from injury, ran onto a pass from the impressive Lopes, beat his marker and chipped the goalkeeper.

Negredo then moved onto 23 goals for the season ― one more than the entire West Ham team has managed in 22 games in the league ― by muscling his way through the home defense and applying a deft finish on the slide.

“We didn’t want to lose,” City defender Joleon Lescott said. “We wanted to keep our winning streak going.”

The 60-year-old Pellegrini is now the brink of winning his first piece of major European silverware, having left Spanish football empty-handed after spells with Villarreal, Real Madrid and Malaga across nine years.

City is also in the running for three other trophies ― it is second in the Premier League, through to the last 16 of the Champions League and in the fourth round of the FA Cup.

To make matters worse for West Ham, midfielders Joe Cole and Mohamed Diame went off injured in the second half. (AP)