Senegalese international Diame turned in another impressive display in the win at the DW Stadium, which lifted United back to the top of the Sky Bet Championship table.
He opened the scoring with a superb effort in the first half, slotting home after combining well with Isaac Hayden to bag his first league goal for the club.
The 29-year-old – who joined Wigan from Rayo Vallecano in 2009 – has come to the fore in recent weeks, having overcome a challenging start to life in a black and white shirt.
And Diame, who also scored against another of his former clubs Hull City last month, feels his confidence is beginning to return.
“It was a strange feeling, but I'm always happy to score goals. It was important to show that I'm an important player for the Newcastle team, and give back the confidence that the manager has shown in me,” he told nufc.co.uk.
“It’s important, and for me it’s good for my confidence as well. Now, I'm looking forward to the next one. I feel my legs are back, the confidence is coming back as well slowly, and now it’s just about keeping on working and getting better every game.
“I scored against Hull, then Wigan – it would be nice if we could play against West Ham now!
“But I'm always happy to score. For Wigan, I really wish that they will stay in this league, because I like this club.”
Diame’s opener came in what was a dominant first half performance from the Magpies.
But Wigan rallied after the break, threatening on occasion before substitute Christian Atsu made the points safe with 12 minutes remaining.
And Diame reserved praise for the impact of Ghanaian winger Atsu, whose clincher came at a vital time.
“It was a good performance in a difficult game, but we've done it. I thought the team worked hard, even when Wigan put us under a bit of pressure, we kept confident and looked for the second goal,” he said. “Christian did well to bring his legs into the game for us, and he did well to get the second goal.
“When he came on he gave us runs in behind the defenders and that helped us all, it helped the team. His finish was a great one as well, so that was good for the team and now we just need to keep going.”
United now face two home games before the end of 2016, with Sheffield Wednesday and Nottingham Forest the visitors on Boxing Day and Friday, 30th December respectively.
“It doesn't matter if you play home or away – we know that if we want to get promoted we need to go for the win every single game,” said Diame.
“We’re going to work hard and see if we can win the next game against Sheffield Wednesday now, and that’s it – that’s what we have to do, and what we have to focus on.”
