The 20-year-old Anderson, who had also taken a wicket with the first ball of Friday’s match, removed all rounder Abdul Razzaq and tail-enders Shoaib Akhtar and Mohammad Sami to wrap up Pakistan’s 44-over innings of 185 at The Oval.
Trescothick then tore Pakistan’s highly rated pace attack to shreds, hitting 86 from 55 balls including 76 in boundaries — 16 fours and two sixes — in blazing sunshine.
The left-hander, using the pace of the ball, hammered three boundaries in an over off Shoaib — who reached speeds of almost 99mph — and Azhar Mahmood, and outdid that with four off Sami.
He also hit two sixes as England, hardly the most stylish of one-day sides in the past, cruised home in 22 overs.
Pakistan, who had won the first match of the series, were left trying to make sense of the carnage.
Shoaib, the world’s fastest bowler, went for 46 off five overs before redeeming himself with the wickets of Michael Vaughan (10) and James Troughton (0), both caught behind.
He also had Vikram Solanki, who had made eight in a first-wicket stand of 109, dropped off a no-ball and, next delivery, spilled at slip.
Shoaib ended with two for 69 from nine overs, while Azhar Mahmood conceded 35 off three overs.
Andrew Flintoff rubbed in the humiliation with three consecutive boundaries off Mahmood to end the game.
England, however, fielding the same inexperienced side that lost at Old Trafford, deserved their luck by putting on a hugely entertaining display.
For Pakistan, there was only one real consolation, Yousuf Youhana’s high-class 75 not out.
They won the toss and little else as Imran Nazir was dismissed lbw by Anderson’s first ball to set the tone.
Their problems soon intensified when four middle-order wickets fell for 19.
Hameed chopped Darren Gough on to his off stump and Younis Khan, rooted to the crease, edged behind first ball to make it 61 for four.
Soon it was 80 for six when Solanki leapt up at gully and, Jonty-Rhodes style, parried a Rashid Latif waft before catching the rebound off Anthony McGrath’s gentle medium pace.
Youhana, with his 27th one-day international half-century, and Mahmood put on 72 to try to patch up the innings before Mahmood pushed hard at a wide Rikki Clarke delivery and was well caught above his head by Solanki at gully for 30.
Anderson, still playing club cricket just a year ago, finished things off, his last ball a perfect yorker for a number 11, before Trescothick took up the baton.
By Shoaib’s second over, he was driving two consecutive half-volleys through extra cover followed by a cut to the fence. Next ball, a 98 mph leg-side wide, also hurtled to the boundary.
Mahmood was treated in similar fashion before Trescothick, on 30, had his one escape, a top-edged pull dropped at fine leg.
Trescothick reached his 13th one-day half-century off 37 balls, including 48 in fours, as 92 came off 10 overs.
After a top-edged six off Shoaib, though, his luck ran out when another towering top edge off Razzaq was caught behind.
Vaughan and Troughton failed before Flintoff hammered England home.
The teams meet again in the deciding last game of the series at Lord’s on Sunday.
Pakistan
Imran Nazir lbw b Anderson 0
Mohammad Hafeez lbw b Flintoff 14
Yasir Hameed b Gough 28
Yousuf Youhana not out 75
Younis Khan c Read b Gough 0
Shoaib Malik run out 2
Rashid Latif c Solanki b McGrath 3
Azhar Mahmood c Solanki b Clarke 30
A Razzaq c Trescothick b Anderson 17
Shoaib Akhtar c Read b Anderson 0
Mohammad Sami b Anderson 0
Extras (b-1 lb-1 w-11 nb-3) 16
Total (all out, 44 overs) 185
Fall of wickets: 1-0 2-37 3-61 4-61 5-73 6-80 7-152 8-185 9-185
Bowling: Anderson 9-2-27-4, Gough 7-1-28-2, Flintoff 8-1-36-1, McGrath 10-1-40-1, Giles 5-0-22-0, Clarke 5-0-30-1
England
M.Trescothick c Rashid b A Razzaq 86
V.Solanki not out 40
M.Vaughan c Younis Khan b Shoaib 10
J.Troughton c Rashid Latif b Shoaib 0
A.Flintoff not out 26
Extras (b-4 lb-4 w-14 nb-5) 27
Total (for three wickets, 22 overs) 189
Fall of wickets: 1-109 2-143 3-147
Did not bat: A.McGrath, R.Clarke, C.Read, A.Giles, D.Gough, J.Anderson.
Bowling: Shoaib Akhtar 9-0-69-2, Mohammad Sami 3-0-25-0, Azhar Mahmood 3-0-35-0, Mohammad Hafeez 2-0-19-0, Abdul Razzaq 5-0-33-1
Man-of-the-Match: Trescothick
First match: Old Trafford - Pakistan won by two wickets.
Third match: Lord’s, June 22.—Reuters