The 6ft 2in Merino’s height and stature make him an obvious threat and so it proved. He stole in to head home powerfully from Ethan Nwaneri’s right-wing cross with nine minutes left, before finishing with confidence after 87 minutes to wrap up the win that leaves Arsenal four points behind Premier League leaders Liverpool having played a game more.

The player himself played down the notion he might figure more as a striker, but on this evidence Arteta may give him no say in the matter as he makes his plans without Havertz and Gabriel Jesus until next season.

Merino said when asked about starting as a striker: “I don’t think so to be honest. It is certainly the first time I have scored two coming off the bench as a striker.”

He told BBC Match Of The Day: “It was big news for me this morning when one of the assistants told me this was an option. It’s the first time in my career that I’ve played in this position, but the good thing is that the way this team plays, everyone knows what to do.

“Mikel told me to use my strengths in the box and I was in the right place at the right time. I’ve not trained there once but I know what everyone has to do on the pitch. Tactically, we are a rich team and I just tried to emulate all the guys who are out injured.”

If Merino, justifiably, grabbed the headlines, it was 17-year-old Nwaneri who was Arsenal’s overall inspiration with a superb performance of skill, confidence, pace and maturity.

Nwaneri delivered the inviting cross for Merino’s opener, having previously hit the woodwork twice in Arsenal’s only serious moments of threat before those late goals.

Arteta was lavish in his praise of Nwaneri, as well as his fellow teenager Myles Lewis-Skelly, who ensured Arsenal stayed on level terms by applying a vital touch to Jordan Ayew’s cross with Bobby de Cordova-Reid waiting to tap in a simple finish at the far post with the scoreline goalless.

He said: “Physically they are built in a really special way already. Emotionally and mentally, how composed they are, and how they make decisions on the pitch are really impressive, so let them go.”

Arsenal’s nerves and anxiety were mounting until Merino stepped into the breach, the lack of a serious central threat obvious as every attempt floundered near goal with Leicester City holding firm.

In among that pre-Merino mediocrity, it was a dismal day for Sterling, who struggled to do a thing right and looked short of confidence and the old pace before Arteta decided he had seen enough.

Sterling looked crestfallen as he walked off, another opportunity missed for the 30-year-old former England forward to show he can still be a going concern at this level as he continues to struggle at Arsenal after being marginalised by Chelsea.

No such problems for Merino, who has not had a full effect in midfield since his Arsenal arrival but may now have the chance to do so further forward as Arteta looks to solve his most pressing problem.

And there was a touch of belated romance about Merino’s heroics and Arsenal’s win as the Spain midfielder said: “I forgot to give my wife something for Valentine’s Day so this goes to her. I think she will appreciate this more than a rose and some chocolate.”

What Mrs Merino’s view is on this we do not know – but what is certain is that it was the best present Arteta and Arsenal could have received.