Kevin Pietersen said Wednesday he has not ruled out resurrecting his international career with his native South Africa even though he'll be pushing 40 when he requalifies.

The 37-year-old batsman will become eligible to play for the Proteas in 2019 having not been selected for England after being sacked in the aftermath of the 2013-14 Ashes defeat in Australia.

"You are talking about in two years' time. Would I? Who knows? We'll have to wait and see where I am," said Pietersen after smashing a thrilling half-century to lead Surrey to a 10-run win over Essex in front of almost 24,000 fans at the Oval in the Twenty20 Blast in an explosive return to English cricket.

"I'm going to be playing a lot of cricket in South Africa over the next two years, so we'll see.

"I love batting: I will bat for as long as I love the art of batting. I do at the moment, but I'm an old man now, I've just hurt my calf, I didn't field.

"Who knows where I'll be in two years' time? If I enjoy batting, we'll see where I get to. I'm in a very happy place."

Pietersen hit four sixes in an over on his way to 52 off 35 balls in a Surrey total of 150 for nine on Wednesday.

In reply, Essex were restricted to 140 for seven.

Pietersen, who suffered a calf injury which prevented him from fielding, was playing his first English domestic match for nearly two years.

He had a lucky escape in the 10th over when he was dropped by Dan Lawrence off Ashar Zaidi and added 43 with Dominic Sibley.

Pietersen was eventually out in the 16th over, three balls after reaching his 40th half-century in T20 cricket.