Chelsea's tormentor Dele Alli is transforming from apprentice assassin into Tottenham's young general

The headline numbers suggest this is the least productive season of the 22-year-old's career, but his role has changed

It was a beaming Dele Alli who strode through the Wembley mixed zone on Saturday evening, trying to suppress a chuckle as he was reminded that Chelsea appear to be his favourite opponent. His early flick-header in Saturday's 3-1 win was his sixth goal in five games against them, and if his reaction had just the ring of the perfunctory to it - “whether it was me or someone else, I’d be just as pleased,” he said - then in reality, it was actually a fairly good snapshot of a career that seems to be developing in new and unexpected ways.

The headline trait of Alli is that he is a player who comes to the fore in big games. That much is undeniable - since the start of the 2016-17 season he’s scored 11 goals against the rest of the top six. He's scored in an FA Cup semi-final and a World Cup quarter-final. He's scored against Real Madrid in the Champions League. “He’s so competitive,” his manager Mauricio Pochettino said. “He’s a player who loves to compete with and beat opponents.” But in a sense, it’s only half the story.

This was just his second league goal of the season; his weighted pass up the right flank for Son Heung-Min his first assist. In his first three seasons at Tottenham, his output was remarkably consistent: a goal or assist every 135 minutes in all competitions. In his fourth season, it’s been considerably down: once every 215 minutes. Injuries have played their part, but Alli’s habit of delivering on the big occasion masks the fact that in terms of pure numbers, this has actually been by some distance the least productive season of his career.

So what’s happening? To find out, you need to delve a little deeper into the numbers. Alli isn’t shooting significantly less: his expected goals are actually marginally up on previous seasons. So a small decline in his finishing is one possible explanation. But perhaps the biggest change has been one of mindset. A player whose many talents have allowed him to drift between roles without ever quite nailing down any single one of them, Alli now seems to be maturing into a midfielder whose athleticism and anticipation make him just as important in defence as in attack.

It’s hard to recall now, but when he first signed from MK Dons, Alli was seen as more of a deep-lying central midfielder, rather than the refined auxiliary forward he would later become. Occasionally you would even see him deployed as one of the midfield two in a 4-2-3-1, the role he played so well in the 4-0 League Cup defeat of Manchester United. The most common comparisons were with Steven Gerrard, which is the sort of comparison you make when you’re not really sure what to make of a midfielder.

After all, Gerrard was a player whose actual function remained famously and spectacularly ill-defined. And Alli’s first season at Tottenham was redolent of that positional skittishness: a few games at the base of midfield, a few on the wing, a few behind the striker. What Pochettino appears to have concluded from that first season, however, was that for reasons of temperament or tactical discipline, Alli was not ready to run a midfield on his own. His sneaky punch on West Brom’s Claudio Yacob, which saw him banned for the title run-in, seems to have been a watershed moment in this respect.

Instead, Pochettino moved Alli up into the final third, shedding some of his defensive responsibilities and converting him into a deadly penalty-box poacher. The results were more or less instant: 19 goals and seven assists in the 2016-17 season, 11 goals and 14 assists last season. The Kane-Alli-Son-Eriksen quadrangle became one of the most effective front fours in Europe, and perhaps in retrospect Tottenham’s relative struggles this season are no surprise when you consider that the Chelsea game was the first time all four had started together in the league for almost seven months.

Alli was pivotal to Tottenham's plan of stifling Jorginho at Wembley (Getty)

This season, however, something has changed. Alli may still be only 22, but he’s had time to hone his craft: more than 100 Premier League games and 33 England caps, two international tournaments and three Champions League campaigns. And along the way - perhaps influenced by Alli’s performances in a midfield three for England - Pochettino has decided that Alli was ready for a little more responsibility. “I think my role has changed a little bit,” Alli admitted. “I’m playing a little bit deeper. I’m not always thinking about scoring goals or assisting. As long as I’m helping the team, whether it be scoring, assisting or defensively, I’m happy.”

Pochettino has been pivotal in this process. Managing Alli, a mercurial character experiencing the extreme stresses of instant fame at a comparatively young age, has been one of his great balancing acts: adulation and encouragement, with the occasional jagged edge. “Sometimes he has done badly for himself,” Pochettino admitted. “Sometimes you need to control the character. But it is never easy for a young guy to be consistent when so many things happen. We are here helping, by being nice, but strong too.”

Alli, for his part, is a fully paid-up member of the church of Mauricio. After the Chelsea game, he discussed the bespoke role Pochettino had created for him, pushing him high onto Jorginho, depriving Chelsea’s playmaker of space and ultimately marking him out of the game. “He’s an amazing manager tactically,” he said. “A lot of it [the win] was the work we did tactically: on the front foot pushing up high. He makes it very clear what you have to do. So going into the game, you know your role, you don’t have to worry about anything else.

“He [Jorginho] is a big part of them playing out from the back and dominating possession. We thought we could stop that, so I wanted to be as close to him as possible, to make sure that we won the ball up high, broke early and created the chances that we did. On another day, we could have scored a lot more.”

And so in a way, the real story of Alli’s season has been not his goals and assists, but his defensive contributions. He’s still not the daintiest of tacklers, but with his long legs and reading of the game he’s one of the best interceptors in the side. Since 2016-17, his tackles and interceptions per 90 minutes have risen from 1.91 to 3.35 this season, a number not seen since his early days at Tottenham, when he was still trying to do it all. Yet perhaps the strongest testament to Alli’s growing maturity is his increasing realisation that he doesn’t have to do it all: in 2015-16, almost half his shots (47 per cent) were low-percentage efforts from outside the area. This season, that’s just 7%.

In a way, it’s the classic developmental arc: from teenage tearaway to apprentice assassin to young general. Alli may not be as desperately decisive as he was in his younger days, but in a way he’s a far more complete player now than he was back then. The big prizes still lie well over the horizon of winter. But for now, smiling and firing, and with Inter Milan and Arsenal coming up this week, Tottenham’s talisman seems ominously primed.