London - Keaton Jennings survived a couple of scares against his native South Africa as England maintained their grip on the third Test at The Oval on Saturday.
England were 74 for one in their second innings, a lead of 252 runs at stumps on a gloomy third day where rain meant only 32 overs out of a scheduled 98 were bowled.
Jennings was 34 not out and Tom Westley, one of three debutants in England's XI, unbeaten on 28 in what is the 100th Test at The Oval.
Johannesburg born and raised Jennings, the 11th man tried as an England Test opener alongside Alastair Cook since Andrew Strauss retired in 2012, was under pressure for his place after a run of low scores - including a duck in the first innings of this match.
The 25-year-old Durham left-hander, England-qualified through his mother and by residence, nearly fell cheaply again to another slip catch by Dean Elgar off Vernon Philander only for an edge on six to be dropped on this occasion.
Earlier, Temba Bavuma's gutsy 52 helped South Africa avoid the follow-on.
His innings was the cornerstone of the Proteas' 175 all out.
That left then 178 runs behind England's first innings 353, which featured Ben Stokes's 112 and former captain Cook's 88.
Toby Roland-Jones, who'd removed all of South Africa's top four in a sensational debut display on Friday, had Bavuma caught behind to end the innings.
Middlesex seamer Roland-Jones finished with figures of five for 57 in 16.4 overs.
In the process he became just the sixth England cricketer, and first since Graham Onions in 2009, to take five or more wickets in a debut Test bowling innings.
"I was very impressed. He's a very intelligent cricketer... and he thoroughly deserved his five wickets," explained fast bowler James Anderson, England's all-time leading Test wicket-taker, who himself took five for 73 against Zimbabwe at Lord's in 2003 during his first innings at this level.
South Africa resumed on 126 for eight, still 28 runs shy of avoiding the follow-on.
Bavuma was 34 not out and Morne Morkel unbeaten on two, with this four-match series in the balance at 1-1.
South Africa were bolstered by knowing Philander had been passed fit after a night on a hospital drip
"Vern is a competitor, he's not someone to give in," said Bavuma who ensured South Africa avoided the follow-on by driving a Stuart Broad half-volley through the covers for four.
But a valuable ninth-wicket partnership of 47 ended when Morkel (17) nicked Anderson to Cook at first slip.
Bavuma's edge to the third man boundary off Roland-Jones saw him complete a hard-earned fifty off 111 balls, including eight fours.
But he was out soon afterwards, edging a good length Roland-Jones ball to wicket-keeper Jonny Bairstow.
Number six Bavuma had come in with the Proteas 47 for four and could only watch as they slumped to 61 for seven.
But he kept South Africa in the game, receiving good support in an eighth-wicket stand of 53 from Kagiso Rabada (30).
"We can save the game, the first target is to bowl them out or prolong the game, but we can bat out four sessions. Looking at us, we have the belief," added Bavuma.
England lost Cook shortly after lunch when he was bowled by Morkel for just seven.
Westley followed his first-innings 25 with another promising effort featuring several well-struck boundaries.
Left-hander Jennings, who again risked bringing the slips into play by several times defending with an angled bat, was on 33 when given out, apparently caught behind, off fast bowler Rabada.
But his review of umpire Joel Wilson's decision showed the ball had pitched just outside the leg stump.
With lbw not an option as a result, it also meant the issue of whether Jennings had got an edge could not be considered.