Amir was the hottest property in world cricket after bursting on the scene as a teenager in 2009.
He was soon earning comparisons with fellow Pakistan left-arm fast-bowler Wasim Akram, with Wasim himself declaring Amir a better bowler than he had been at the same age.
At 18, Amir was the youngest bowler to have reached the landmark of 50 Test wickets.
His first 14 matches in the five-day game saw him take 51 wickets at just a fraction over 23 apiece — figures that had Amir on course to be an all-time great.
But Amir's world was turned upside down in 2010 when he and Mohammad Asif became involved in a spot-fixing scandal after deliberately bowling no-balls during the Lord's Test against England at the behest of then Pakistan captain Salman Butt.
In 2011 Amir was given a five-year ban by the International Cricket Council and sentenced to six months in jail by an English court.
Amir returned to international duty in 2016 but his 16 Tests since his comeback have yielded 44 wickets at a relatively expensive 37.25.
"We want more from Amir, as bowling coach I want more from Amir," Mahmood told AFP after the paceman took one wicket for 45 runs in 15 overs during Pakistan's drawn tour opener against Kent at Canterbury on Tuesday.
"If you see his record since he came back it's not great, but he was coming back after five years out," the former Pakistan all-rounder added. "He needs to take a bit more responsibility and get more wickets for us. If he's the leader of this attack, he needs to show us a bit more. I'm sure he will do that and that's what we want from him."
Given his lengthy absence it is unsurprising that the now 26-year-old Amir has not quite scaled the heights he reached earlier in his career.
Nevertheless, there have been some memorable moments since his return, with Amir taking a superb 3-16 in six overs as Pakistan thrashed arch-rivals India by 180 runs in the final of last year's Champions Trophy one-day tournament at The Oval.
Amir's figures against Kent on a cool, if sunny, day were nothing like as spectacular.
Inzamamul Haq warns Pakistan of tough English conditions
This, however, was a warm-up match, with Pakistan next facing Northamptonshire before providing the opposition for Ireland's inaugural Test and then returning to England for a two-Test series.
And one delivery from Amir, who served part of his prison sentence in Canterbury jail, stood out on Tuesday when he demolished the stumps of Alex Blake with a late-swinging yorker.
It certainly caught the admiring attention of Kent assistant coach Allan Donald, the former South Africa fast bowler.
"When I saw this kid a few years ago, he's one of the most skilful that's going around," said Donald. "When you saw him knocking over those 'poles' that's exactly what you expect from him — so much skill, so much imagination and creativity to produce that sort of thing on flat pitches."
He added: "When it gets flat, you have to think out of the box and to see that happening was an eye-opener."
Meanwhile Donald predicted Pakistan, whose last Test series in England ended in a highly creditable 2-2 draw in 2016, would impress again this year.
"There are some seriously good players in this Pakistan team," he said. "I think it's going to be a great series — I hope it warms up for them though."
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ