The pair shared the opening two frames before Holt seized the advantage with a break of 115 in the third which he followed up by taking a tight fourth frame.
Further breaks of 97 and 60 were enough to see Holt progress into the second round.
"If I'm honest, it doesn't surprise me when I beat anyone," said Holt. "My career has been very disappointing because I want to be a champion but for whatever reason it hasn't happened.
"Results like this might surprise the public because they never see me play well. I go on television and lose."
Trump said: "Michael played well and deserved to win. I'm very disappointed because I had a good run here last year. It's frustrating to come such a long way and lose in the first round."
Former UK champion Stephen Maguire suffered a shock 5-2 loss to Xiao Guodong.
Breaks of 89, 54 and 69 saw the home hope progress to the last 16, and a meeting with Peter Lines on Thursday.
"It's more about my opponent's bad performance, because I wasn't playing that well," said Xiao.
"He didn't put me under pressure during the first four frames so I was really relaxed. I had a chance to close the match in the fifth frame but he managed to fight back, which affected me somehow. He's ranked higher than me and his game is better than mine.
"After that every frame went scrappy but I found the key to win the match and I'm happy to be in last 16."
John Higgins and Neil Robertson suffered few problems as they opened their tournaments with comfortable 5-1 victories over Mike Dunn and Wang Yuchen respectively whilst Mark Selby also progressed after a 5-2 win against Lin Shuai.
In other first round matches, Kyren Wilson 21, completed a memorable 5-1 win over Stuart Bingham, Martin Gould overcame Ricky Walden 5-3 with Mark King compiling knocks of 106 and 70 in overcoming Graeme Dott 5-3.
"It's nice to still be in the tournament. Graeme was below his normal standard. I struggled in patches but made a couple of good breaks," said King, who will face Neil Robertson for a place in the quarter-finals.
First round results
John Higgins 5-1 Mike Dunn
Mark Davis 5-2 Ali Carter
Peter Lines 5-4 Matthew Stevens
Xiao Guodong 5-2 Stephen Maguire
Kyren Wilson 5-1 Stuart Bingham
Marco Fu 5-0 Cao Yupeng
Martin Gould 5-3 Ricky Walden
Michael Holt 5-1 Judd Trump
Mark Selby 5-2 Lin Shuai
Robert Milkins 5-4 Mark Joyce
Ryan Day 5-1 Mark Allen
Barry Hawkins 5-0 David Grace
Shaun Murphy 5-4 Yu De Lu
Ding Junhui 5-2 David Gilbert
Mark King 5-3 Graeme Dott
Neil Robertson 5-1 Wang Yuchen