The Brazilian caught the eye throughout the month, with two goals - including the winner against Fulham at Craven Cottage - helping to secure another personal accolade.
Speaking as he was presented with the award, the 26-year-old said: "I have been missing these - it's my first one this season. It's a good moment. I think I've been playing well, so this one is very special for me."
Having rounded off April with a goal in the 5-1 victory against Sheffield United at St. James' Park, he admitted that his performance against the Blades was spurred by a Wor Flags display dedicated to the Magpies' fan favourites from South America.
"It was very positive to see the Brazil flag for me and Joe (Joelinton) before the game," he said. "I made an effort to not cry on the pitch because it was beautiful. I want to thank the fans as they have been unbelievable with me. The fans have given me so much - I've never felt so loved.
"I went into the game thinking, 'I have to score a goal for them today'. It was an important goal so I'm very happy."
Guimarães also emphasised his determination to repay supporters throughout the final stage of the campaign, adding: "As I've said before, we have to finish top six. That's all we've been thinking about.
"We have four more games so we have to play well. We'll put the focus on the next game against Burnley. We'll go there and try our best to get three points as it's going to be very important for us."
Voting for the Sela Player of the Month takes place after every match in the club's post-match email.
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