The 19-year-old announced his arrival in test cricket by blazing a wonderfully entertaining 129 on day three of the first test against New Zealand, in Dunedin.
• Slideshow: Highlights from New Zealand vrs Pakistan At the University Oval.
His innings and 176 sixth-wicket stand with brother Kamran Akmal led Pakistan back from the brink.
The tourists had slumped to 85 for five thanks largely to a remarkable spell of fast bowling by Shane Bond.
Pakistan reached 307 for eight by stumps and still trail by 122.
New Zealand resumed at 404 and added a further 25 runs.
The home side is in a strong position if it can pick up the remaining wickets quickly.
But the day belonged to Umar.
The confident youngster dispensed with the nervous 90s, blasting Iain O'Brien for a six over long on and whipping a boundary through wide midwicket to bring up the milestone.
He celebrated by kissing the ground and raising his bat to the heavens.
He is the 11th Pakistan player to score a century on debut.
Long-serving Dunedin coach Billy Ibadulla was the first Pakistan player to achieve the feat.
After the day's play, Umar revealed a telephone call home to mum had helped inspire him.
"She said she will be praying for him and she hoped he would score some runs. She told him to just relax and take it easy - but he didn't listen to her," said Pakistan team manager and translator Intikhab Alam.
"It was his dream come true to make a hundred on his debut. I feel very proud of him. He's a very exciting cricketer, actually."
It was a marvellous innings and, as a batsman, Umar is no shrinking violet.
He bludgeoned 16 fours and two sixes in his 100.
But moments later the celebration turned sour as his older brother, Kamran, was dismissed for 82, slashing at a delivery from Daniel Vettori.
Umar angrily whacked his pads with his bat in disappointment for his brother, who had helped nurse him through his own innings.
Despite 54 overs lost to poor weather on day two, New Zealand decided against declaring.
Bond whacked a four through the covers and a six over long on before he copped a short delivery from Mohammad Asif and gloved it through to the wicketkeeper.
Chris Martin was able to extend his impressive collection of test ducks when he was trapped lbw by Saeed Ajmal.
He has now been dismissed in a test without scoring on 26 occasions.
West Indies fast bowler Courtney Walsh is the undisputed chump, with 43 ducks, with Australian Glenn McGrath tucked in second place, with 35.
Martin is back in fifth equal.
Come on mate, lift your game.
Getting out was the best thing he could do for the team in retrospect.
The much anticipated return of Bond to the bowling crease was worth the wait.
Playing in his first test in two years, the 34-year-old quickly got into his stride and generated plenty of pace.
But he did not graduate until after lunch.
It was Martin who had the early success.
He removed Khurram Manzoor with a rank short and wide delivery, which should have disappeared to the boundary, and trapped Imran Farhat in front.
The afternoon session was as good as it gets.
New Zealand backed Pakistan up against the ropes, with Bond producing an inspired spell of fast bowling.
The speedster removed danger man Mohammad Yousuf with a brilliant return catch and nicked Fawad Alam out with a rising delivery which hit the deck hard and brushed his gloves on the way through to the keeper.
Shoaib Malik paid for a rash cut shot and got a thick inside edge on to his leg stump.
Kamran edged the next snorter, but it dropped short of Ross Taylor at first slip, and Umar narrowly avoided calamity when he ducked to avoid a bouncer but left the periscope up.
Moments later, he got lucky again when a thick edge defeated Daniel Flynn in the gully.
When Bond's magnificent spell came to an end he had taken three for 25 from seven overs.
He picked up his fourth wicket late in the day's play when Umar offered a catch.
