There is every chance that Dom Sibley will finish his first home summer as a Test cricketer as England's highest run-scorer. As things stand, he is second only to Ben Stokes in the charts, who will miss the final two Tests due to family reasons; since his debut in November, only Stokes and Joe Root have been more prolific.

With that in mind, it is something of a surprise to hear his assessment of his time in the side so far. "I do feel, sitting here now, that I've got a lot more to give," he said on Tuesday. "I've only sort of shown myself to a certain level at this stage, and I do feel like I've let opportunities slip to score maybe four or five hundreds. That might be sounding greedy and it might sound unrealistic but that's the way I think."

That mentality has served Sibley well to date. After piling on the runs in county cricket last season - he scored 300 runs and faced 1000 more balls than anyone else in Division One of the County Championship - he has bedded into his spot at the top of the order after an unconvincing start, with hundreds against South Africa and West Indies and an average a shade below 40.

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And yet there have been several occasions - most notably in the two Manchester Tests against West Indies - when Sibley's presence at the crease has provoked groans and mutters. His strike rate across the course of his career is a sedate 36.57 - 2.19 runs per over - and his caution against spin in particular has been a point of frustration for those hoping England will accelerate.

"I am trying to learn and improve as much as possible," he said. "That's the thing that I probably need to do a bit better, especially against spin, is to try and rotate the strike as much as possible; be a bit more proactive. I've been working really hard on that." He has picked the brains of Graham Thorpe, England's assistant coach and himself a strong player of spin, as well as asking some of his team-mates for advice.

But in the first Test against Pakistan, his desire to show a more proactive side to his game against spin proved his undoing in the second innings. Yasir Shah had joked to England's batsmen on the fourth day that conditions in Manchester suited him even better than those in Dubai. And after padding away two overs of legspin from round the wicket, Sibley was suckered into a drive when Yasir came back over, slashing to slip and muttering in frustration to himself as he dragged himself off.

"I was obviously extremely disappointed with the way I got out in that second innings because I had worked really hard, [and had] been really disciplined against him," he said. "I did feel like I wanted to be that person, not out at the end when we chased that down. But it wasn't to be and you try and learn from those mistakes.

"It's a fine balance, I suppose, because I want to be out there and put such a high price on my wicket and do a good job for the team. But at the same time, trying to find that balance between [that and] having the bravery to play the shots that I feel like I know I have in the locker.

"It's just a case of having the bravery and confidence to do that in the Test arena when the scrutiny is higher and you might get judged in how you get out."

In particular, Sibley has realised when batting with Root - who averages 63.38 against spin over the course of his career, rattling along at a strike rate of 59.50 in the process - that there is work to be done. And while he is happy with his record against spin in county cricket, he is aware that with more attention on him, it might not be so easy to drop anchor.

"I feel confident in playing spin and I have done. When you get to this level, and suddenly loads of eyes are on you, and you may not be scoring as quickly as other people in the team, you get judged.

"I have always felt very confident and scored runs against good bowlers in country cricket. But when you get to international cricket, with the spotlight being on you, you get those things pointed out a bit more. It's made me think that I need to work a bit harder.

"When you are batting with someone like Rooty at the other end who is making playing spin look pretty easy, it makes me think that I need to try and take my game against spin to the next level."

With as many as seven Tests in Asia in the pipeline this winter - two in Sri Lanka, and five in India or UAE - there is a sense that this biggest challenge is still to come.

Matt Roller is an assistant editor at ESPNcricinfo. He tweets at @mroller98