England beat South Africa by just two runs to win the second one-day international at Southampton on Saturday to take an unbeatable 2-0 lead in the three-match series.

South Africa, set 331 to win, finished on 328 for five, with Quinton de Kock making 98.

The world's top-ranked ODI side needed 20 off the last two overs when David Miller (71 not out) struck Jake Ball for a six and a four off successive deliveries.

Yet with a mere 10 now wanted off as many balls, South Africa -- often accused of 'choking' in pressure situations -- saw Miller and Chris Morris fail to score the runs they required as Ball and fast bowler Mark Wood both held their nerve.

Earlier, Ben Stokes made 101 and Jos Buttler a dashing 65 not out as England posted a total of 330 for six after losing the toss.

The series, a warm-up for the Champions Trophy tournament in England and Wales that starts next week, concludes at Lord's on Monday.

Ben Stokes made South Africa pay for dropping him twice in his first two balls with a century that powered England to 330 for six.

There had been some doubt over whether Stokes would play Saturday after briefly leaving the field with left knee trouble during England's 72-run win at Headingley on Wednesday.

But ahead of next week's Champions Trophy tournament in England, the all-rounder showed no discomfort with the bat.

His 79-ball innings, just his second century in 55 matches at this level, featured 11 fours and three sixes.

Stokes, the Indian Premier League's record two-million-dollar-man, shared stands of 95 with skipper Eoin Morgan and 77 with Jos Buttler.

After Stokes fell, Buttler kept up the attack with a dashing 65 not out as England looked to go 2-0 up with one to play in this three-match series.

South Africa, the world's top-ranked ODI side, dropped six catches during a sloppy fielding display, with left-arm spinner Keshav Mahraj three times denied a wicket in his debut at this level.

The luckless Maharaj bowled much better than figures of one for 72 in 10 overs suggested.

Proteas captain AB de Villiers opted to field first after winning the toss in overcast conditions that promised to aid swing movement.

South Africa had an early success when Jason Roy was bowled trying to whip a Kagiso Rabada yorker legside.

Alex Hales, dropped on 18 when a six off Maharaj went straight through Rabada's hands at long-on, was still on 24 when well caught by wicket-keeper Quinton de Kock, standing up to the stumps, off Pretorius.

SCORES IN BRIEF

ENGLAND: 330 for 6 (Stokes 101, Buttler 65 not out, Morgan 45; Rabada 2-50)

SOUTH AFRICA: 328 for 5 (de Kock 98, Miller 71 not out, de Villiers 52; Plunkett 3-64)

Result: England won by two runs

Player of the Match: Ben Stokes