Under other circumstances, the main cause for celebration would have been that Manchester United qualified for the Champions League’s knockout stages for the first time since David Moyes was a few months into his six-year contract and Marouane Fellaini was Old Trafford’s newest signing. As it was, in the lowest-profile match of a high-stakes week, sandwiched between games against Arsenal and Manchester City and when progress was all but guaranteed, the most important element could be the goal that might spur Romelu Lukaku into another scoring spree.

“His work for the team every match is crazy,” said José Mourinho, a supportive voice during his £75m signing’s drought. “If I could choose goalscorers, I would always choose the strikers. If he can feel that happiness that strikers only get when they score goals then great.”

Lukaku began his United career with 11 in 10 games. This was just his second in 13 subsequent matches and a first meaningful strike since September. It was beautifully taken and, besides a statistical significance, his equaliser should increase morale and momentum, not least his own. United were trailing, their 39-game unbeaten run at Old Trafford and 100% home record this season under threat, when Lukaku volleyed in Paul Pogba’s delightful ball.

If it was a reminder of how much United will miss their record signing on Sunday, when Pogba begins a three-match suspension for his red card at Arsenal, two goals in as many minutes were both fashioned by superb passes. A swift turnaround was concluded when the influential Juan Mata lofted a ball over the visitors’ defence. Marcus Rashford completed an unusual one-two by angling in the winner to earn the goal he had threatened from the off. He had struck the post in the fourth minute, springing the offside trap to meet Lukaku’s pass, and had used his pace to torment a CSKA Moscow back three with a combined age of 102 and his persistence to keep the goalkeeper Igor Akinfeev busy.

Rashford started, as Mourinho made six changes with City in mind. Even with seven players injured or rested it was notable that Henrikh Mkhitaryan was omitted altogether for the fifth time in six games. Luke Shaw, another who has felt Mourinho’s displeasure when marginalised, began for the first time in 219 days, almost scored his first career goal with a volley Akinfeev parried and drew rare praise from his manager.

“It was a very positive performance, especially going forwards,” he added. “He was deserving of that opportunity for quite a long time and he is going to get more.” In the short term, however, demotion beckons as others return. Mourinho ruled Eric Bailly and Michael Carrick out of the derby, while adding: “Phil Jones has a chance, Fellaini a chance, Zlatan [Ibrahimovic] a big chance and [Nemanja] Matic is injured but will play for sure.”

Their absences meant progress was a squad achievement. “Fifteen points in a season returning to the Champions League is good,” said Mourinho. It would have taken a seven-goal defeat, which United have not suffered since 1931, plus a victory for Basel over Benfica to eliminate them. That always appeared improbable but a first home defeat since City’s last visit to Old Trafford was on the cards when CSKA led in bizarre fashion.

Vitinho’s shot went in via Alan Dzagoev’s back as United appealed for offside. Referee Gianluca Rocchi rightly ruled that Daley Blind, who had slid off the pitch in an attempt to cut out Mário Fernandes’ cross, had played Dzagoev onside. Uefa muddied the waters by crediting Vitinho with the goal but Mourinho conceded it was correctly given.

Thereafter, Sergio Romero was required to make a late save to deny Dzagoev an altogether more conventional equaliser, while Mourinho was left pondering if United’s reward for topping Group A will be a meeting with Real Madrid or Bayern Munich. “I am not the luckiest guy with draws,” he said sardonically. “It is better I shut up and forget it.”