The difference with club level sport is that skill and technique can vary much more widely than you see at international level (where fitness is often the only difference between teams).
That means a team that is less fit but has more talent will mostly outplay the fitter and less skillful side.
But that's not the whole story
Conditioning gives the edge
All other things being equal it is your cricket specific conditioning that gives you the edge.
For example, in a close game where sides are roughly equal (say, the national stages of the North Gear 2020 Premier League where standards will be high). It would take a very unlucky or mentally unprepared team to lose if they are physically capable of playing hard to the last ball:
- Faster batsmen can steal more runs.
- More powerful players can hit more boundaries.
- Fitter bowlers can maintain pace and accuracy even at the death.
- Less tired fielders have better concentration and reactions.
All the technique in the world is no good if you can't maintain it under fatigue. That's why, even as club cricketers, we should look at our diet and fitness plan on the same level as our technique practice.