He was dismissed in the 41st over, after defending a delivery from Kyle Jamieson into the ground and then swatting the ball away with his right hand after it had bounced up wide outside off stump. New Zealand appealed immediately and it was upheld by the TV umpire Ahsan Raza.
At the end of the day's play, Mushfiqur's team-mate Mehidy Hasan Miraz suggested that the action had been an instinctive one.
"It happened in the flow of the game," Mehidy said. "A batter has to take a split-second decision while at the crease. His hand probably went in the flow of his batting. Mushfiq bhai didn't do it intentionally. A lot of things happen in the back of your mind during a game. We got a time-out dismissal in the World Cup, so these things happen."
On TV commentary, former Bangladesh captain Tamim Iqbal reckoned the dismissal could have come about as a reflex, because batters practising in the nets often pick up the ball and throw it back to the bowlers.
"A cricketer who has played over 80 Tests should know he can't do that," Tamim said. "Practice habit can make this happen. In the nets, batters often take the ball in hand and return it back to the bowler. Maybe Mushfiqur did it unconsciously and extended his hands. But this obviously can't be an excuse."
While such dismissals were classified as "handled the ball" previously, a change in the laws in 2017 removed the "handled the ball" category and brought it under "obstructing the field".
According to Law 37.1.2, "The striker is out obstructing the field if, except in the circumstances of 37.2, in the act of receiving a ball delivered by the bowler, he/she wilfully strikes the ball with a hand not holding the bat. This will apply whether it is the first strike or a second or subsequent strike. The act of receiving the ball shall extend both to playing at the ball and to striking the ball more than once in defence of his/her wicket."
Handled the ball was brought under obstructing the field to streamline the mode of dismissals, according to the MCC, because in effect the former was a specific case of the latter. "The reason for the change was largely based around timing. For handled the ball, the offence had to be in the act of receiving the ball and it was felt to be simpler to include it as obstructing the field, of which it was a special example. A batter handling the ball later (e.g. blocking a throw deliberately) would have been obstruction and so it was decided it would be easier to include handling the ball within the obstructing the field Law. Whether or not the batter would be dismissed did not change - rather just the method of dismissal."
Ball 40.4 wasn't the first time Mushfiqur had attempted to touch the ball with his glove during his innings in Mirpur. In the 29th over, the first after lunch, he had tried to knock the ball away from the stumps with his right hand but failed to make contact.
The wicket eventually came against the run of play, after Mushfiqur and Shahadat Hossain had added 57 for the fifth wicket, steering Bangladesh from 47 for 4 to 104 for 5. Mushfiqur was dismissed for 35 off 83 balls.
New Zealand left-arm spinner Mitchell Santner said the dismissal was a fortunate one for his team, given the position Mushfiqur had batted Bangladesh into.
"It was probably not a great option [from Mushfiqur]," Santner said. "He was looking so good. I mean it was handy for us in terms of the time. Him and Dipu [Shahadat] applied themselves and that was a very good partnership for them."