London : Moeen Ali scalped a hat-trick as England wrapped up a huge 239-run win over South Africa on the fifth day of the third Test at the Oval to take an unassailable 2-1 lead in the four-match series here on Monday.

Chasing a daunting target of 491 runs to win, South Africa made a poor start to their second innings, losing opener Heino Kuhn for just 11 runs.

Kuhn's opening partner Dean Elgar waged a lone battle as he smashed 20 boundaries in his blistering 136-run knock to make England sweat for victory.

The only support Elgar found was from Temba Bavuma (32) as the duo shared a crucial 108-run stand after the Proteas collapsed to 52 for four on Sunday.

Off-spinner Ali was at his menacing best on the final day as after Elgar, he took a hat-trick of Chris Morris (24), Kagiso Rabada (duck) and Morne Morkel (duck) to bundle out the Faf du Plessis-led side for 252 runs. He finished with the overall figures of four for 45.

The hat-trick was also the first at the Oval in 100 Tests and the first by an England men's team spinner since 1938.

Meanwhile, Toby Roland-Jones, who bagged a brilliant five-wicket haul in the South Africa's first innings, continued his dream England debut by clinching three wickets during the visitors' second innings. The Middlesex paceman struck twice in two balls before lunch to dismiss Temba Bavumaand Vernon Philander.

Ben Stokes took two wickets while Stuart Broad also chipped in with a wicket.

Earlier, Jonny Bairstow (63), skipper Joe Root (50), Tom Westley (59) and Keaton Jennings (48) all contributed with the bat as England declared their second innings at 313-8.

Ben Stokes, who also scored a sparkling 112-run knock in the first innings to help his side post 353 runs, was declared `Man of the Match` for his all-round performance.

The two sides will now play an inconsequential Test at the Old Trafford from August 4.