Mauricio Pochettino could see the surprise on the features of his audience. Nobody had expected this. Harry Kane was supposed to return from his ankle ligament injury for the north London derby against Arsenal at the end of April – not the faux-derby with Watford, the club to the north of London, on Saturday. But, to a borrow a phrase from Wayne Rooney before the World Cup in 2006, the Big Man is back.

Pochettino made it plain that his only decision concerned whether to name Kane in the starting XI for Watford’s visit or introduce him as a substitute. One thing that the manager said suggested he was leaning towards the former.

In Kane’s absence, which began in the opening minutes of the FA Cup tie against Millwall on 12 March when he rolled the ankle in grisly fashion, Tottenham have done well. They went on to batter Millwall 5-0 and they have won all three of their Premier League fixtures.

Son Heung-min has deputised more than ably in the No9 role and his stoppage-time goal was decisive in last Wednesday’s 3-1 win at Swansea City. Son has scored 16 goals in all competitions this season, a fact that seems to have drifted under the radar. Could Kane even face a battle to reclaim his starting place immediately, Pochettino was asked.

“Maybe I am crazy but you cannot put a doubt on Harry Kane,” he replied. “There is no doubting that Harry is our best player. It’s like with Barcelona – Messi is injured for one month but Barcelona are still winning. Then, Messi is available again and you say: ‘Hmm, I don’t know?’”

Pochettino’s mention of Kane in the same breathe as Lionel Messi said it all. The 23-year-old’s early return is a tonic on many levels and it will allow him to get up to speed for the FA Cup semi-final against Chelsea on 22 April and the Arsenal game on 30 April. Tottenham’s Premier League pursuit of Chelsea has received a fillip.

Kane has pushed himself during his rehabilitation and, having returned to training earlier in the week, he was pushing Pochettino on Friday. He tends to do this. When Pochettino orders him inside after the extra shooting practice that he insists upon after sessions, there can be cross words. Pochettino’s mood was lighthearted here. There was a sense of happiness but, also, reassurance.

“Today was good because after training, he was shooting, he was playing and you can see that he is ready,” Pochettino said. “I said: ‘Hey, Harry. I don’t know if you are ready or not.’ He says: ‘No, no. I want to be involved tomorrow.’ So, I said: ‘No. You will not be involved.’ He asked why. I said: ‘Your answer is wrong. You should say: ‘Gaffer, it’s up to you because you are the manager and you decide. If you say this, then you will be involved tomorrow!’”

Kane was out from mid-September for seven weeks with an ankle ligament problem and, across the season, Tottenham have played eight league games without him. They have won five and drawn three, which shines a positive light on the depth of the squad that Pochettino has assembled.

Hugo Lloris missed the Swansea match because of a stomach bug but he trained well on Friday, meaning he should return against Watford. If not, Pochettino will give a debut to Pau López because his second-choice goalkeeper, Michel Vorm, is out with the knee problem that he suffered against Swansea.

Pau, who joined on loan from Espanyol last summer, is Spain’s Under-21 goalkeeper and Pochettino rates him highly. Tottenham have the option to make the transfer permanent at the end of the season for €7.5m (£6.4m). Pau caused controversy last season when he appeared to stamp on Messi during Espanyol’s Copa del Rey defeat at Barcelona.

“It was a derby,” Pochettino said. “He is very competitive and has a strong character. He is still very young but he played 36 games in La Liga last season. He needs to learn and improve but he is ready – physically and mentally.”