Nottingham - Under-pressure England opening batsman Adam Lyth is on the verge of a "big score" according to Alastair Cook, but the captain's confidence is not shared by Kevin Pietersen.
"He (Lyth) hasn't scored the runs he would have liked but in the last game his method looked a lot more solid even if he didn't get the runs," Cook told a news conference ahead of Thursday's fourth Test against Australia at Trent Bridge.
"But I do believe there is a big score around the corner."
Left-handed Yorkshireman Lyth's top score in six innings during the Ashes series is 37 and on three occasions he has failed to reach double figures.
Outspoken former England skipper Pietersen, who averaged 47 in 104 Tests, expressed his doubts that Lyth has the quality to make the grade as a Test opener.
"Like several others before him, Adam Lyth is finding out the difference between Test cricket and County cricket," he said in his role as ambassador for betting firm Paddy Power.
"It's a huge step up and you don't get as many loose deliveries. He needs to be busier at the crease - occupy it more and look like he owns it and belongs there.
"At the moment, it looks like he's there to defend. It looks like he could get out on every single ball. That's no way to be at the top of the order."
With bowler Jimmy Anderson injured for the Trent Bridge match, which could clinch the series for England who lead 2-1, Cook believes another hero could emerge, be it Lyth or even fast bowler Mark Wood who is favourite to replace Anderson.
"There is an opportunity for someone to really make their name in the history of English cricket, whether it is to score a big hundred or take six wickets," Cook said.
England dominated the first and third tests, but were demolished at Lord's in between and Cook is wary of his side's inconsistency as they prepare for Trent Bridge.
"For two out of three games we've played some really good cricket but we've been consistently inconsistent over the last seven games," Cook said.
"We can't control how they play but we can control how we bat, bowl, field, and how we go about our business.
"If we put the ball in certain areas to their batters we can put them under pressure, if we don't, like at Lord's, we'll get punished."