The 23-year-old, returning to the club after a loan spell at Sheffield United, made a crucial stop to deny Tom Lockyer as United went into the final 10 minutes of their third-round tie with a slender 1-0 lead from Juan Mata’s penalty on the stroke of halftime.
Dean Henderson's bid to replace David de Gea as Manchester United's first-choice goalkeeper got off to a solid start as he made a key save in his belated debut for the club in their 3-0 win at Luton Town in the League Cup on Tuesday.
Henderson was one of 10 changes to the United team after a disappointing 3-1 home defeat to Crystal Palace on Saturday in their opening game of the new Premier League campaign.
The 23-year-old, returning to the club after a loan spell at Sheffield United, made a crucial stop to deny Tom Lockyer as United went into the final 10 minutes of their third-round tie with a slender 1-0 lead from Juan Mata's penalty on the stroke of halftime.
Henderson, who arrived at the club from Carlisle United at the age of 14, clawed the ball away to keep his side's lead intact and they went on to make sure of victory against the second-tier side with late goals from Marcus Rashford and Mason Greenwood.
"That is probably the job our keepers sometimes have to do, you have to make saves when needed and David (de Gea) has done that for years and Dean did that today," said manager Ole Gunnar Solskjaer.
"It was very important because it was 1-0," added Mata to Sky Television at the final whistle.
"He did a great save and somebody also cleared the ball on the line. I think we did OK. We have all not been training together for too long and now it is important to get the rhythm back and to get confidence. The confidence comes with results."
Henderson tweeted afterwards: "I dreamt about this my whole life!! Unbelievable feeling to make my debut for the club I love!! Clean sheet and a win to top it off!!!"
He will now look to depose Spain international De Gea who has been the subject of criticism this year but made some good stops at the weekend against Palace at Old Trafford.
The win over Luton got United back to winning ways and Solskjaer was pleased with their progress to the fourth round where they will face Premier League side Brighton & Hove Albion or Championship team Preston North End.