England have built a lead of 189 runs over South Africa after reaching 2-53 in their second innings at lunch on day three of the fourth and final Test.
After dismissing South Africa for 226 earlier on Sunday, England forged on as they seek to seal a series victory at Old Trafford.
England lead the series 2-1.
The hosts lost Alastair Cook and Tom Westley early, and were 2-30, but their 136-run first innings lead ensured they are in a strong position.
Keaton Jennings, out of form and desperate for a score, was 17 not out and captain Joe Root was with him on 13 not out in England's second innings.
Morne Morkel took both wickets for South Africa in the morning session, but the Proteas face an uphill task to limit England to a manageable lead and give themselves a chance at saving the series.
South Africa, 9-220 overnight, lasted less than four overs, with Stuart Broad removing No.11 Duanne Olivier to collect figures of 3-46.
James Anderson finished with 4-38 at his home ground.
