In what was his first Test innings, Mahmood shared a valiant stand of 90 with Jack Leach as the tail-enders hauled England to 204 all out after a dismal display from the top seven.
Mahmood managed to put on the best batting performance of his career in Grenada, although the 25-year-old was eventually dismissed in the final over of the day for 49.
His total was 15 more than he'd ever previously achieved in his professional career, and it seemed as though the rest of the England squad had written him off before he even took to the field.
As Mahmood prepared to bat, other England players were seen on the balcony in their whites, anticipating a short stint until fielding duty.
However, Leach and Mahmood formed a strong partnership, and held on for a further two-and-a-half hours.
After sparing England's blushes, Mahmood admitted post-match that it was something he had spotted.
"We did spot that," he said.
"I did say it to Leachy - 'the cheeky f****** have got their whites on'. It did spur us on a little bit."
With the rest of the team seeming to lack faith in their ability, Mahmood reserved praise for Leach after the match.
"I had a glance over later to see if some had taken them off but they left the whites on throughout. It was good fun out there with Leachy, it was a case of being disciplined out there and hitting the bad ball. We knew they'd get to a stage where the sting was taken out of their attack.
"It could have easily fallen into pieces after the start we had in the first two sessions but we stuck at it well."
Mahmood also revealed that he is usually confident in his ability with a bat, and was frustrated to fall just short of what would have been a spectacular half century.
If you hear me in the dressing room I'll always talk myself up as a batter, but when you come into this environment and you've got guys bowling 145-150kph you tend to go quiet a little bit.
"But it would have been nice to get 50. I got a bit of tunnel vision and probably took my eye off the ball."