Ms Berger said she was absolutely delighted by her victory
Labour candidate Luciana Berger was elected in Liverpool Wavertree as the party successfully defended all its Merseyside seats.
Ms Berger, who attracted controversy among some quarters because she is from London, secured a majority of 7,167 over her Lib Dem rival, Colin Eldridge.
The Conservatives made three gains in Cheshire, securing City of Chester, Weaver Vale and Warrington South.
Liberal Democrat John Pugh successfully defended Southport.
Labour candidate Andrew Miller retained his seat in Ellesmere Port and Neston, but the result was delayed until Friday afternoon because of a clerical error in counting the postal votes.
His seat was one which the Conservatives were hoping to win.
Speaking about her victory in Wavertree, Ms Berger - who had faced criticism for her perceived lack of local knowledge - said she did not expect such a large winning margin.
"I'm absolutely delighted. It's a fantastic testament to every single person from the Labour Party who came out and volunteered," she said.
In a closely-fought contest in Weaver Vale, Cheshire, Tory candidate Graham Evans was elected with a majority of just 991 votes over Labour's John Stockton.
Stephen Mosley took the City of Chester seat with a 2,583 majority over Labour's Christine Russell.
Mr Mosley described his win as a "good victory for the Conservative Party".
"Chester should be the jewel of the north west. I need to work with the council, with other agencies to get the investment into Chester and bring it back and put it in its rightful place," he said.
On Merseyside, Labour held Birkenhead, Bootle, Halton, Knowsley, Liverpool Riverside, Liverpool Wavertree, Liverpool West Derby, Liverpool Walton, Sefton Central and St Helens North.
It also secured notional holds in Wallasey, where Work and Pensions Minister Angela Eagle achieved a 8,507 majority, and Wirral South where Alison McGovern was elected.
In Garston and Halewood, Equalities minister Maria Eagle took a 16,877 majority.
Derek Twigg was re-elected as MP for Halton, a seat he has held since 1997, with 23,843 votes - a 15,504 majority.
Elsewhere in Cheshire, the Conservatives' Stephen O'Brien held his Eddisbury seat with an increased majority of 13,255. Labour held Warrington North.
The Lib Dems had a strong showing in the constituency where candidate Robert Thompson came second with 22.5% of the vote.
In Knowsley, the party could not compete with Labour where George Howarth retained his seat with a 25,690 majority - more than 70% of the vote.
Earlier, a polling station in Liverpool Wavertree ran out of ballot papers because of an unexpectedly high turnout and officials had to send for more.