Joe Denly knows England must find a way to halt their batting collapses after South Africa built a 175-run lead on day two at Centurion.
Denly was England's top scorer with 50 on Friday as the tourists were all out for 181, losing their final seven wickets for just 39 runs.
James Anderson, Stuart Broad and Jofra Archer led the England fightback with the ball, restricting South Africa to 72-4 by stumps.
However, Denly acknowledged England's batsmen must now step up if Joe Root's side are to keep themselves in contention in the first Test of a four-match series.
"It's frustrating. It felt pretty comfortable out there. Myself and Ben [Stokes] were starting to get a really good partnership going. I managed to nick one and we lost a few wickets after that," Denly told Sky Sports.
"We spoke at tea about trying to bat long, keep them out there as long as we could. It wasn't to be in the end but a great fightback at the end.
"We have spoken about trying to get those first innings runs. It's trying to assess the conditions a bit better, understanding game situations, where we're at, who's bowling, trying to get through those tricky periods and wear them down that way.
"You have to be clear in your plan. What is the surface doing, how the bowlers are trying to get you out and working together as a partnership, get through those tough periods.
"We're in a stronger position than where we could have been. A big morning coming up and hopefully the batters can get some runs."
Denly was dropped while still on zero, though looked comfortable at the crease up until he reached his half century, succumbing to Dwaine Pretorius three balls later.
"It was tough, a very impressive opening spell [from South Africa], very high-class bowlers and they challenged us. It was tough," Denly said when asked about his performance.
"I was just being patient, I knew it was going to be tough and they were going to make me work hard for every single run, but it was just a case of being patient and sticking to my plan of trying to have a tight defence and seeing off [Vernon] Philander and [Kagiso] Rabada to start with.
"Once the new ball wore off, it was hot off there as well, so they couldn't charge in for too long, I managed to find a bit of fluency."