Robinson opened his United account early in the second period, heading home an Oliver Norwood free-kick following Rhian Brewster’s earlier strike against Nathan Jones’ side.
Heckingbottom has spoken frequently about his desire to sign a new centre-half before the transfer window closes later this month, which in turn has intensified the focus on Robinson after slips during United’s recent games at Wolverhampton Wanderers and Derby County.
But Heckingbottom said the former Liverpool, Queens Park Rangers and Nottingham Forest defender’s effort was just reward for the application he has shown in the face of adversity.
“I didn’t realise that was Robbo’ first goal for us,” Heckingbottom said. “He’s responded well and done really well for me. We are going to have players who make mistakes. It won’t be those mistakes that make players fall out of favour with me. It will be a lack of effort. And that’s not something you can throw at Jack, no way.”
The visit of Luton, who saw Reece Burke sent-off with around half-an-hour renaming, marked United’s first appearance at Bramall Lane since the end of November, following a series of Covid-19 related postponements over the Christmas and New Year period.
“I was pleased with the win and I was pleased with the performance,” said Heckingbottom, after criticising United’s display during Tuesday’s draw with a Preston side which had also been reduced to 10 men. “I was pleased to put that one to bed.”