Hard-luck tales bring added torment in the relegation zone and they are mounting for Roberto Martínez and Wigan. For the second festive-season game in succession the Wigan manager was left bemoaning a crucial penalty decision as Leon Osman, with a fortuitous goal at one end and a reprieve at the other, gave Everton the winning edge.

On Saturday it was Theo Walcott's tumble that incensed Martínez and cost Wigan a point against Arsenal. On Boxing Day it was Shaun Maloney's fall in the Everton area that stirred similar emotions in the Spaniard as his team were denied a valuable draw on Merseyside. Martínez was right to lament an outcome that did not reflect the Wigan performance, but to pin it on the referee Lee Mason's interpretation of Osman's challenge on Maloney was debatable. The Scotland international appeared to be going to ground before making contact with the Everton midfielder's knee. Arguably, the real source of Martínez's ire was the time-honoured tradition of borderline decisions going against the struggling club.

"The penalty was clear and it was the reason we didn't get the positive result that we deserved," said the Wigan manager, whose team are firmly ensconced in the bottom three but, just like last season, appear to have the class and belief to mount a recovery. "You will see the contact clearly on the replays. Maloney is past, Osman doesn't follow the player, and sticks his leg out. You could hear the contact from where I was on the bench and I was bemused he didn't give the decision.

"The reaction of Osman tells you everything. He ran away thinking he got away with it. He wasn't angry, he didn't try to say that Maloney had dived. Contact was very clear and I couldn't believe it. As an experienced referee you know that he didn't need to dive because he was in a great position one on one with the keeper, so that's why the decision was a real surprise."

David Moyes, who in contrast to Martínez was able to savour the result above the performance, was closer to the truth with his assessment of an incident that came six minutes after Osman had put Everton ahead. He said: "From the dugout I thought it was a penalty but when you look at it again there is debate over whether there is contact or not."

Everton have now taken 68 points in this calendar year, the highest total since their last title-winning year of 1987, but this was a scrappy display that was influenced more by Osman's intelligence when moved into central midfield than his outstretched leg on Maloney.

Aside from howling for a penalty when a series of corners produced the customary wrestling matches, Everton rarely threatened a breakthrough in a first half as grim as the weather. Their control of the game was frequently undermined by a careless final pass and it was Wigan, with their five-man midfield stifling Everton, who carried the greater threat.

The second half, however, brought a change in urgency and fortune from the home side who took the lead when Osman was allowed time to check on to his left foot outside the Wigan area. The England international's shot lacked power but took a vicious deflection off the inside of Gary Caldwell's arm and completely wrong-footed Ali al-Habsi in goal.

Thomas Hitzlsperger struck the Wigan bar from 30-yards as Everton looked to dominate, but the threat from Martínez's men remained. Mason's refusal to award Maloney the penalty prompted a furious reaction from the Wigan players, however – Jean Beausejour was booked for man-handling the referee – and their many banana-clad supporters.

Phil Jagielka appeared to put beyond Wigan with a towering header into the top corner from a cross by Phil Neville, making the 500th league appearance of his career. But Arouna Koné ensured a nervous finale for Everton after Franco Di Santo's shot had spun into the air and despite appearing to use an arm, the Ivory Coast forward squeezed between Sylvain Distin and Leighton Baines to score from close range.

Moyes added: "We have drawn a lot of games this season and in the last five or six minutes it looked as though it was going to be tight, but we had opportunities to extend our lead at 2-0. Wigan are a good team, they don't get the credit they deserve for how they play, and this is a good win."