Wigan edged into an early lead when Victor Moses out-jumped Michael Williamson to hand Martínez’s side the initiative in the 13th minute, and the Nigerian forward scored a second shortly after.
The Latics extended their lead when Shaun Maloney tucked his finish under Newcastle goalkeeper Tim Krul, before Franco Di Santo scored a spectacular fourth on the stroke of half-time to seal Wigan’s third victory in a month which included wins over Arsenal and Manchester United.
“The difference [on Saturday] was that we took our chances,” Martínez told BBC Sport.
“Since early February we had good levels of performance and played really well but you need to take your chances. We had belief, arrogance, call it what you like [against Newcastle].
“The first half display was as good as against Manchester United – the team showed great maturity and it’s a very strong clean sheet. At this stage of the season that’s very important.
“This is the biggest month in the history of our club, playing against Manchester United, Arsenal and Newcastle.
“In every department of the club we know need to work really hard to keep our dream alive and that comes with belief.
“It’s great to beat these sides but that means nothing if we can’t achieve our aim. Our aim is to stay in league and we haven’t got enough points. We have two big games left, big finals.”
Newcastle did have chances of their own, and Papiss Cissé was twice denied his 12th league goal since joining from Bundesliga outfit Freiburg by Wigan goalkeeper Ali Al-Habsi.
Alan Pardew admitted Wigan deserved their victory over his Champions League chasing side but the Newcastle boss was pleased by the Magpies’ response after half-time.
“We just didn’t match their intensity,” Pardew said.
“Forget shape, systems and so on, intensity is everything in football. For the first two goals we were really lose and disorganised. It was not until half-time that we got back to our level and showed discipline.
“We were honest in the second half, showed pride and at Chelsea on Wednesday we will show the intensity we’re used to showing and give them a far stronger game. If you were here today you’d have to say we got beat by the better team.”
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