Martinez said: “I think some of the games they were very unfortunate not to get the three points. Overall I think their performances have been very consistent. “They had a couple of injuries and maybe against West Brom is the only time they changed their formation a little bit and had to adapt, and that was a really tough game. Apart from that game, they’ve been in every game. “They’ve been very strong, even against Chelsea. We all know how strong Chelsea have been this season. They had the opening goal and they had a couple of good opportunities and they never stopped giving a good level of performance. “We don’t take Burnley by the results they’ve had. I look at Burnley by what they’re capable of.” Everton also had a difficult start, largely due to the amount of goals they were conceding, but appear to be back on the right track. Last weekend’s 3-0 win over Aston Villa was followed on Thursday by a goalless draw in Lille in the Europa League. Martinez said: “As a team we wanted to start the season brightly and we really embraced the expectations that we brought into the season. “Early in the campaign we conceded too cheaply and that affected the scorelines; I don’t think we played badly at all. That’s why you can see the team is getting stronger and getting sharper and the reflection in the scoreline has been there. “The reaction of everyone has been really brave and mature and I would say now we are a stronger team than we were at the beginning of the season. “I’m really excited with the full potential of this squad, which is starting to show really good signs for the months ahead.” James McCarthy, Seamus Coleman, Steven Naismith and Leon Osman could all return to the Everton side. Naismith and Osman were left out of the travelling party for Thursday’s Europa League trip to face Lille while Coleman was an unused substitute and McCarthy played only the last few minutes. The Toffees have no new injury worries but Kevin Mirallas (hamstring) and John Stones (ankle) remain sidelined while Bryan Oviedo and Arouna Kona are still not match-fit. Burnley defender Michael Duff has vowed to prove the critics wrong as the Clarets go in search of their first Premier League win at the ninth time of asking. Last week’s 3-1 home defeat to West Ham has led many to write off the chances of Sean Dyche’s side staying in the top-flight as they prepare to take on Everton at Turf Moor on Sunday. But the 36-year-old Duff – the only member of the team remaining from Burnley’s last Premier League campaign in 2010 – maintains the belief has not left the current squad despite their frustrating run of results. Duff said: “It happened last year when people kept writing us off and saying we wouldn’t get promoted and we just kept all that noise out and believed in ourselves. “Nothing changed this year – it’s just a different kind of noise. We’ve got belief in ourselves and we don’t think we’re too far away. If we keep performing well hopefully things will change for us.” Dyche’s injury problems are slowly beginning to ease with Steven Reid pushing back into contention while Dean Marney could also feature against Roberto Martinez’s men having missed the last three games with a hamstring problem. Duff does not need reminding how the Clarets’ last top-flight campaign came to abrupt end but he conceded that in the four years since he was last at the highest level, the nature of the league has changed completely. Duff added: “The teams have changed and the managers have changed but with the amount of money that’s swilling around in the league even the so-called smaller clubs are attracting £10million or £15million players and it’s hard for us to compete. “The learning curve is massive. Last Saturday was a big one – we totally dominated the first half against West Ham and probably should have been leading at half-time but we weren’t. “We switched off for 12 or 13 minutes at the start of the second half we we went 2-0 down and the game was dead and that’s the reality. “We did all right but the gaffer has made it clear to us that he’s not all right with us doing all right. We need to win games if we want to stay in this league and we know we have to address that.” Burnley midfielder Dean Marney remains a doubt. Marney has missed the last three games with a hamstring injury and will be given a late test by the club’s medical staff. Steven Reid and Michael Keane are pushing for recalls after groin and hamstring problems respectively, but Matthew Taylor remains absent as he awaits an Achilles operation. Press Association He said of Sunday’s game: “It’s a huge challenge because I saw Burnley play a lot during last season and they are a really strong unit. “I think they play as a team, they know each other really well, they’ve got really good energy. I think the start they had in the Premier League has already given them very good experiences and I know it’s going to be really tough to face them on Sunday. “It’s difficult to describe the job that (manager) Sean (Dyche) has done. Going into a team that had no expectations to get promoted and all of a sudden they played a very dynamic and exciting brand of football that gave them promotion. “They’ve been able to play eye to eye against any team that they’ve faced already. They got a good draw against Manchester United at home and Sunderland. “You’re going to get defeats in this league but they never stop competing. They got a really important point against Leicester showing that mentality and togetherness. “We know we’ll have to be at our best and we don’t underestimate how difficult it’s going to be.” Scoring goals has been Burnley’s big problem – they have managed just four – but they have kept clean sheets against Manchester United, Crystal Palace and Sunderland. Their only heavy defeat was a 4-0 loss to West Brom while last time out they could not take advantage of a dominant first-half performance in losing 3-1 to West Ham. The Toffees travel to Turf Moor on Sunday with the hosts still looking for their first victory following promotion back to the Barclays Premier League in May. Burnley sit second bottom of the table with four points from eight games, a tally Martinez thinks does not reflect their performances. Everton boss Roberto Martinez believes Burnley have been unfortunate not to pick up a win so far this season.