England allrounder Ben Stokes has conceded his troublesome knee is affecting his bowling following his match-winning hundred against South Africa in Southampton.
Man-of-the-match Stokes made a superb century before England sealed a stunning last-ball win in the second one-day international to go 2-0 up with just one to play ahead of Monday's finale at Lord's.
The allrounder, who struck 11 fours and three sixes in 79 balls as he equalled his highest ODI score of 101, told Sky Sports: "It's always nice hitting the ball well and knowing you've got a bit of form behind you."
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Jos Buttler chipped in with a dashing 65 not out as England's dangermen hit form less than a week out from Thursday's opener against Bangladesh.
"We've seen Jos hitting the ball nicely, which is great for us going forward," Stokes added.
"Hopefully we can just continue going forward and continue this form into the Champions Trophy."
Stokes, however, bowled just the three overs on Saturday having suffered a knee injury in England's 72-run win in the first ODI at Headingley on Wednesday.
Although scans on the injury were inconclusive, Stokes was deemed in good enough health to play on Saturday, though he conceded afterward the injury was having an impact on his bowling.
"It's just the bowling that's getting affected by my knee," said Stokes.
"Batting, fielding and running around isn't an issue."
The right-armer is set to have a further scan on the knee this week.
"It comes and goes. I have bad days and good days," he told BBC Sport. "I'm not sure if it is a worry or not, it might just be wear and tear. Hopefully we'll get a clearer picture (with the scans).
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"It's just the bowling. When I land on the floor I get a pain on the outside of my knee, so we just need to find out what that is.
"I was able to bowl today, but at the end of my third over I started to feel it.
"It's a confidence thing as well.
"If I feel the knee I don't feel I'm running through the crease properly."
South Africa, chasing 331 to win after England made 6-330, saw opener Quinton de Kock make a stylish 98.
Further half-centuries from skipper AB de Villiers (52) and David Miller (71 not out), plus some powerful hitting from Chris Morris, took the Proteas to the brink of victory.
They needed seven off the last over but were denied by England fast bowler Mark Wood, finishing on 5-328.
England captain Eoin Morgan said the fact his side had prevailed in a close finish augured well for their Champions Trophy chances.
"I think the tournament is bound to be pretty tight," said Morgan of an event featuring the world's top eight ODI sides.
"There are a lot of good teams around so this sort of prep today I think is ideal."
De Villiers did his best to put a brave face on a loss that saw the Proteas, top of the International Cricket Council's ODI rankings, drop six catches.
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"I thought the boys played exceptionally well at the end there," he said.
"(But) you've got to give credit to the last two bowlers for England.
"They showed some great skill and good plans."
Champions Trophy 2017 Guide
Group A: Australia, New Zealand, England, Bangladesh.
Group B: India, South Africa, Sri Lanka, Pakistan.
26 May – Australia v Sri Lanka, The Oval
27 May – Bangladesh v Pakistan, Edgbaston
28 May – India v New Zealand, The Oval
29 May – Australia v Pakistan, Edgbaston
30 May – New Zealand v Sri Lanka, Edgbaston
30 May – Bangladesh vs India, The Oval
1 June – England v Bangladesh, The Oval (Day)
2 June – Australia v New Zealand, Edgbaston (D)
3 June – Sri Lanka v South Africa, The Oval (D)
4 June – India v Pakistan, Edgbaston (D)
5 June – Australia v Bangladesh, The Oval (D/N)
6 June – England v New Zealand, Cardiff (D)
7 June – Pakistan v South Africa, Edgbaston (D/N)
8 June – India v Sri Lanka, The Oval (D)
9 June – New Zealand v Bangladesh, Cardiff (D)
10 June – England v Australia, Edgbaston (D)
11 June – India v South Africa, The Oval (D)
12 June – Sri Lanka v Pakistan, Cardiff (D)
14 June – First semi-final (A1 v B2), Cardiff (D)
15 June – Second semi-final (A2 v B1), Edgbaston (D)
18 June – Final, The Oval (D)
19 June – Reserve day (D)