Roberto Martínez has cited Romelu Lukaku’s staying power as a major influence on Everton’s consistency and the Belgium international’s prolific form this season.

Everton host Crystal Palace on Monday with their £28m record signing having scored six goals in five matches and 13 in total. Lukaku’s appearance record this term is also impressive, with the 22-year-old missing only 39 minutes of Everton’s campaign so far – the result of his late substitutions by Martínez.

The Everton manager believes the centre-forward’s availability has enabled the likes of Gerard Deulofeu and Ross Barkley to shine and reflects the former Chelsea forward’s improvement since last year’s World Cup.

“Every foreign player has to adapt to the physicality of the Premier League but, for a striker like Rom, with his frame, I don’t think he had the opportunity to play enough 90 minutes when he first arrived,” said Martínez. “He had an incredible scoring ratio at West Brom but I think he played only seven full 90 minutes that season.

“It’s a long process to get to the stage where you can play 90 minutes without losing the power and the pace in every action but now it’s very rare that you don’t see him finish the last 10 minutes with the same power, pace and control. On top of that, he can play three games in a week, which is quite remarkable for a player of that size. I would say that’s happening now for the first time this year. At the start of last season, he was catching up after the World Cup. From January, he’s been the mature Rom who can play 90 minutes, and there’s everything that comes with that.”

Despite Lukaku’s obvious importance to the Everton side, Martínez insists he has the options to cope without his leading striker should injury or loss of form occur.

The manager added: “Any player who can stay fit and reliable gives you an incredible base to work on. You can develop a good strategy with other players around them, the understanding of those players, the partnerships you develop. That’s important and, of course you don’t want to lose players through injury. Rom is in a great moment of form. Gerard is in a great moment of form. Ross is in a great moment of form.

“But I feel we’ve got a very good group of experienced players who at the moment are not playing a big role, and they’re ready to play that big role. It’s not the case that our squad is 11 plus three or four young players waiting to help. We’ve got Steven Naismith, Kevin Mirallas, Aaron Lennon, Aiden McGeady, Darron Gibson and Mo Besic. You’re talking about players who are desperate to have a big role. So I’m delighted with the squad that we have.”