Brecel, who at 17 years and 45 days became the youngest player in the history of the tournament, left the arena smiling despite losing 10-5 to Scotland's world number seven, a former semi-finalist in Sheffield.
Brecel showed flashes of his quality during the opening session, in which he made his first century on snooker's most famous stage, but he was always behind and Maguire goes on to play either Graeme Dott or Joe Perry in the second round.
Belgian teenager Brecel, who won four qualifying matches to reach the main draw, was 6-3 behind heading into this morning's concluding session.
He had been 6-1 behind at one stage but clawed two frames back last night with breaks of 116 and 62, and followed those with an 86 in today's opener.
Maguire soon took charge though, and runs of 101 and 94 saw him over the line.
Brecel thrilled the crowd at times with some rapid break-building, but a rash of unforced mistakes cost him.
He said: "I found the crowd really enthusiastic and really enjoyed it.
"The Crucible was a little bit special, different to everywhere I've played before.
"I know I can play so much better. But I want to be back next year and the future will be a different story."
Brecel will finish the season outside the world's top 64, but it would be a major shock if he was not awarded a place on the tour for 2012/13.
"I haven't been told about a wild card for next season. No one has mentioned anything to me about getting one," he said.
"I'm thinking positively about the future."
Asked about the prospect of becoming world champion in future, Brecel said, "Yes, easy", before revising his answer, saying: "Yes, it's definitely possible."
Maguire was pleased to come through his opening test, and at the time managed to enjoy the sight of Brecel in full flow.
The Glaswegian said: "I was excited to play him, not because it was his first time here but because of his talent.
"He's a potting machine isn't he. He's one of the fastest players I've seen and he's fearless.
"It was important I got off to a good start to put him under the cosh a little bit, but once he started letting his cue go he didn't look like he was going to miss.
"I was glad we stopped at 6-3 last night because it was starting to get a bit scary out there.
"He definitely had his chances and missed a few when the balls were sitting well. Lucky for me he missed a couple of big shots when the balls were sitting pretty and that made the difference in the end."