It is now more than six weeks since Chris Wilder left the club and his former assistant was put in caretaker charge.
After an encouraging start, United’s promotion challenge has stuttered and a 1-1 draw with Cheltenham Town on Tuesday night means they have collected just two points from the last five games.
Chairman Ian Lenagan has made it clear getting the appointment of a new manager right is his priority.
But in his most recent interview, which came before the U’s collected one point from back-to-back home games, he admitted results would play a factor in how long Lewis was in charge for.
Lenagan said: “It will only be at the end of the season if Mickey gets us back on the winning trail, obviously.”
The caretaker boss, whose side visit leaders Chesterfield on Saturday, acknowledged two victories from ten games was not good enough.
But he was buoyed by the performance against Cheltenham, which followed on from a strong second half in defeat to Burton Albion on Saturday.
When asked whether he was the right man for the job at the moment, Lewis said: “Yes. It’s not true that I’m happy with the way it’s going because I wanted more wins on the table.
“But I think the lads have shown their spirit and the good football they’ve played, especially in the second half against Cheltenham.
“That’s 135 minutes where we’ve performed pretty well, so we go again on Saturday.”
With many of their rivals also struggling, United are not out of contention for automatic promotion, but the gap to the sides outside the play-offs has been slashed from 13 points to just five.
While some fans have seen the slump in results as a sign United need to bring someone in quickly, Lewis is still popular with the players.
Winger Ryan Williams hopes the 49-year-old is in charge at least until the end of the campaign.
He said: “I think Mickey’s a really good leader, he knows how to set up the team and knows how to manage us as players.
“I think I can speak on behalf of all the boys and say we’d love Mick to stay in charge until the end of the season.
“I couldn’t really see anyone else coming in at the moment.”