Ole Gunnar Solskjær’s dream start continued with a fifth victory in five games but the first stern test of his interim reign is next: the trip to Tottenham next Sunday. The run equals Sir Matt Busby’s non-wartime club record, but how United fare against a team 10 points and three places better off will be a litmus test of progress.

After the downing of Reading ensured safe passage to the FA Cup fourth round, Solskjær batted away the proposition that United had enjoyed an easy run of matches. “When you go to Cardiff in the first game it’s never easy,” he said. “At home you’re expected to beat Bournemouth and Huddersfield, never easy games. There are no easy games in the Premier League. Newcastle away, I thought that was a professional performance.

“It’s never easy when you make nine changes but we still won. Spurs away, Wembley, that’s a proper test. That will give me more of a reference for where we are against the top boys.

“We’re not happy talking about fifth, sixth or fourth in a year or two. The club needs to move on and move up the table.”

Towards the end, Alexis Sánchez was forced off with an injury. “Hopefully he will be OK,” Solskjær said. “He was feeling his hamstring.”

United were hardly the well-oiled machine of recent weeks, as Solskjær kept only Phil Jones and Juan Mata from the team who started Wednesday’s 2-0 win at Newcastle while the Reading manager, José Gomes, made four changes from the Reading side who lost 4-1 at home to Swansea on Tuesday, drafting in Liam Kelly, Liam Moore, Callum Harriott and Danny Loader.

Solskjær had conceded that making so many changes was a risk and United’s disjointed display demonstrated it. He said: “I made it hard for the players because it’s a team that’s never played together. Reading made it really difficult. We never had a kick for the first five minutes, they just kept possession and we weren’t cohesive enough in our pressing.”

An early Scott McTominay header was one warning from United and better was the quick and slick back-to-front sequence that had Sánchez nipping inside from his left channel and shooting only marginally too high to trouble the Reading goalkeeper, Anssi Jaakkola.

United’s were soon ahead, courtesy of VAR. As Mata touched the ball off to Fred, Omar Richards took the Spaniard down. Fred found the net and was ruled offside, but after a rather lengthy consultation the video official gave a penalty that Mata dispatched with aplomb.

Sánchez is in the mould of the kind of tricky, goalscoring forward Solskjær favours. The problem has been a lack of goals and lack of trickery since he signed a year ago. The latest evidence of the his struggles came as the interval neared. Yet again, he had the ball in a dangerous area but got his feet mixed up, and Jaakkola was able to clear.

Sánchez showed some backbone by continuing to take on creative responsibility and eventually it worked. He threaded a pass into Romelu Lukaku. The centre-forward left Jaakkola a spectator and as the angle narrowed he deftly slotted home.

Just as United’s goalkeeper, Sergio Romero, had been forced to save a near-post Andy Yiadom effort moments before Lukaku’s strike, so the keeper had to be sharp to repel a shot by Harriott from near the penalty spot.

United’s response came via a Mata attempt that was stymied and later some neat one-touch stuff involving Diogo Dalot, McTominay and Fred that turned midfield possession into a rapid attack.

Just after the hour, Solskjær made a double switch, taking off Fred and Mata for Marouane Fellaini and Tahith Chong, the 19-year-old Dutchman making his debut. Sánchez was then replaced by Marcus Rashford. He and Chong tried to increase the pace of United’s attacks but were sucked into the general mediocrity on show.

Still, an FA Cup victory achieved when below par is always welcome, while Gomes now returns to trying to stave off relegation. The Reading manager was happy with the Championship team’s display but would like to sign “five, six players” in the transfer window.