Johan Botha remains upbeat despite South Africa falling 4-0 behind in the NatWest Series.
England can move above the Proteas for second place in the world one-day rankings with victory in the final game of the series in Cardiff on Wednesday.
But off-spinner Botha is still hoping the tourists, who lost captain Graeme Smith to a tennis elbow injury after the second match, can avoid a whitewash.
"The big thing when we came over here was to win the Test series," said Botha, who was not part of the touring squad that triumphed 2-1 in the Tests earlier in the summer.
"But, personally, I do think this has taken a bit off the Test win.
"I think the Test team lost a bit of momentum at the Oval (fourth Test defeat), and England have gone from strength to strength from there.
"This last two-and-a-half, three weeks have been very disappointing for us.
"We want to turn it round one last time here - like England did in the Tests - so we can go away with a good game behind us."
As for his own form, Botha accepts he has yet to put in a big performance - but he believes he is capable.
"I'm feeling pretty good at the moment," he said.
"I haven't scored a lot of runs or taken a lot of wickets in the series - but I still feel good."
Botha has taken four wickets at 23.25 apiece in the series and is not worried about the short, straight boundaries at the SWALEC Stadium for Wednesday's day-nighter.
"It does look a little short at one end, but I hope it's still far enough," he added.
"I hope it's quite dry under the covers and it will just stop and turn a bit."