Partnerships script wins, mostly. Rarely, you'll find a one day cricket match where a pair of batsmen broke all sorts of records together but their team ended up losing the match. On such intriguing battle was faught at Lord's on 12 June 2001 when Pakistan had put up moderate 242 on board but England were reduced to 3 wkts for 26 when Owais Shah joined Somerset opener Marcus Trecothick and together, they collected 170 runs from exactly 30 overs which still stands as the highest partnership in England v Pakistan ODI. Sadly, as soon as this record stand ended, home team lost remaining 5 wickets for 44 runs to lose the game by 2 runs.
Marcus Trescothick made 137 and was second last batsman out while Shah contributed patient 62 from 94 balls. Trecothick and Shah, that day, broke record held by Pakistani right handed pair of Rameez Raja and Saleem Mallik on 20 October 1987 with their 167 run stand at National stadium in Katachi. It a World cup match in which opener Raja and no.3 Saleem Mallik drove their team home to 7 wicket victory.
Recently, in 2006, Mohammad Yousuf and Younus Khan notched up another 167 run partnership against England at Rose Bowl in Southamton while Saeed Anwar and Inzamam-ul-Haq also have a 150 run stand in the table mentioned below.
Biggest opening partnership in Eng v Pak ODI is between Robin Smith and Michael Atherton = 147, also at Karachi on 3 March 1996. It was a world cup match and Atherton + Smith had put visitors in command but Pakistan chased their target of 250 down inside 47.4 overs thanks to rocket innings by Saeed Anwar, Ijaz Ahmed and Inzamam-ul-Haq. Another big partnership failed England.