Ole Gunnar Solskjaer believes Manchester United are back on course as the 1999 treble hero prepares to take the wheel for the 100th time.

Parachuted into the Old Trafford hotseat initially as a temporary replacement for Jose Mourinho in December 2018, the Norwegian has been on a rollercoaster ride as he attempts to get the club back to the top.

October has been a microcosm of such highs and lows, with the month starting with a chastening 6-1 home loss to Tottenham and ending in a jaw-dropping 5-0 Champions League win against RB Leipzig.

United kick-off November with a home clash against Mikel Arteta's Arsenal on Sunday, when Solskjaer – to his shock – will reach a century of matches in charge.

"Arsenal is always going to be difficult because they are a very good team with a good manager, who's got some great ideas on how football should be played and I'm looking forward to it," the United boss said.

"I am surprised it's 100. It's gone really quickly, even though a lot has happened.

"So, let's hope I can celebrate number 100 with a good performance and a result. I've enjoyed it so far."

Solskjaer led United to third in the Premier League and three cup semi-finals in his first full season in the hotseat, but a truncated pre-season laid the foundations for a stumbling start to 2020/21.

Skipper Harry Maguire admitted it felt like they "were in a big crisis" after the home defeats to Crystal Palace and Spurs, but there has been a heartening response to the concerning performances.

"Well, I think any result as brutal as a 6-1 would have to get a response and, of course, it has been dealt with internally," Solskjaer said.

"We've tweaked a couple of things, we've got players fit and I think the manner of defeat wasn't something that we should ever have to be confronted with again.

"Then again, things happen in football these days but the response has been fantastic and that's what I'm concerned about. We wanted to finish that off as soon as we could and just move forward."

Solskjaer underlined the need to keep working and developing ahead of the Old Trafford encounter with Arsenal, who United will face without Alex Telles after the deadline-day signing tested positive for Covid-19.

There are no other fresh concerns for the Norwegian to contend with, nor is there the chance for him to utilise or safeguard the squad as effectively as he would like as this unrelenting season continues.

While five substitutes are allowed to be used in European competition, Premier League clubs voted against its implementation having used it during Project Restart.

"100 per cent (I would like to have seen it) and I don't understand and cannot believe that the vote went against because we have to look after the players," Solskjaer said.

"We have to think about the players because this season is the most demanding season of all.

"I can see the point why clubs voted against but if you take a step back and think about these professional footballers and their mental and physical health, I think the only sensible solution would have been to give us the opportunity to rest a few more.

"We have already seen loads of injuries in the Premier League. I know Pep has been talking about it, other managers.

"We as managers, as clubs, as staff, medical staff, we have to look after them.

"That's why we have to rest players at certain times so, yeah, I would have liked to have had five subs."

United have so many options to call from that internationals Sergio Romero and Phil Jones were omitted from the Premier League and Champions League squads.

"Sergio has just come back into training this week, so he's started his pre-season work and is working to get to his peak fitness with the goalkeepers," he said.

"Phil has been injured and he's had an operation and he's working really hard to be back. He'll hopefully get fit during December.

"That was a natural thing, when you're injured you can't really be in the squad, can you? He's working really diligently and he'll be coming back soon."