Raheem Sterling’s birthday gifts for Manuel Pellegrini reflect his growing value at Manchester City

£49m forward scored twice against Borussia Monchengladbach on Tuesday night

Raheem Sterling embraces City manager Manuel Pellegrini (PA)

Literally and figuratively, Raheem Sterling came of age in the Etihad Stadium on Tuesday night.

He had spent most of his 21st birthday asleep, preparing for the encounter with Borussia Mönchengladbach that would determine whether Manchester City finished first or second in their Champions League group.

By the end of it, he was standing near the home dressing room discussing his most electric performance since becoming England’s most expensive footballer. His manager, Manuel Pellegrini, had asked him to celebrate the evening with a couple of goals and Sterling had done precisely that. There had also been an outrageous back-heel to set up David Silva for Manchester City’s opener.

“This is definitely my number one birthday,” said Sterling. “I couldn’t have asked for much better. It was a bit boring in the beginning with people messaging me asking how my day had been when I had been asleep for about 16 hours.

“It was the second time the manager has said something to me and it has come true. Against Seville, he said: ‘I think you can get one tonight,’ and I did.

“I definitely feel I have come of age. Most importantly, my self-belief has changed. I take everything I hear – it goes through one ear and out the other. Football is all that matters to me.”

For Sterling, this season could have gone either way. His leaving of Anfield had been a bitter, bloody affair and the price City paid was just shy of the £50m Liverpool had received when Fernando Torres joined Chelsea.

Torres had sunk without trace at Stamford Bridge and Sterling must have feared that the same might happen to another player swapping a red shirt for a blue one.

Apart from one uncomfortable afternoon last month, when Liverpool’s travelling supporters mocked him as Manchester City were humiliated in their own stadium, the transition has been smoother than he could have hoped.

It may be because there is so much talent and money at Manchester City that Pellegrini’s future did not rest on whether Sterling pulled through – the club paid Wolfsburg even more for the creative talents of Belgium’s Kevin de Bruyne, who proved an instant hit.

“I wouldn’t say 100 per cent that it makes it more easy. It just gives you more of a belief you can play alongside these guys for many years to come,” said Sterling.

“There are great personalities throughout this club and everyone wants to show their ability. I have pushed myself really hard. There have been times I have doubted myself and criticised myself because I know where I want to be.

“I criticise myself because I know what I am capable of. When you are out on the world stage, the most important thing is to show people I can play regularly and consistently.

“There are definitely players out there that I model myself on. I look at the biggest players in the world, see what they have got, and learn.

“I try to learn from watching Messi and Ronaldo, in the way they base their lives around playing football. I know it is obvious but they take the game so seriously. They know they are the best players in the world and it is that confidence that makes them unique.”

This is Sterling’s second successive season in the Champions League. The first – Liverpool’s return to the competition after five years away – was, for all the fanfare, a crushing disappointment. They won only one game and that was against a club, in Ludogorets of Bulgaria, that few at Anfield would even have been aware of.

Sterling, like Steven Gerrard, began the most glamorous fixture of them all – Real Madrid in the Bernabeu – on the bench as Brendan Rodgers rested players for the Premier League fixture against Chelsea. Both games were lost.

This time he has been part of a Manchester City side that has come through at the top of the most difficult of the four groups in which English sides were drawn.

While City did not keep a clean sheet in any of their six matches, they only failed to score in one – away to Juventus. In both games against Borussia Mönchengladbach they came from behind to win.

“With the players we have got here, you know something could pop up at any moment,” Sterling said. “Even when the game looks dead, we can spin it on its head. That gives you faith in the team.”

Pellegrini was hired to take Manchester City to the knockout stages and, provided they do not draw Paris Saint-Germain – a fixture that, with one club owned by Abu Dhabi and the other by Qatar, would be a battle of the mega-rich – they should have little to fear in the round of 16.

“When we are on top form and playing well, I think we can beat most teams,” said Sterling. “And if this team gets through the next round, then anything is possible.”