First came the claims that he was a one-season wonder - now the only question is why Mo Salah has been so muted in his celebrations since climbing to the top of the Premier League goalscoring charts. 

The Egyptian seemed to give no reaction to his hat-trick against Bournemouth last weekend and likewise, after his crucial winner against Napoli that secured Liverpool's pass to the last-16 of the Champions League. 

The 26-year-old endured a difficult summer, suffering with the shoulder injury he sustained at the hands of Sergio Ramos and subsequently failing to shine at the World Cup. 

Then came a comparatively slow start to the season. It's all added to the feeling that Salah isn't enjoying his football quite as much as he used to, whatever the reason for that may be. 

Curiously, the only place where his quiet demeanour doesn't seem to have caused a stir is within the Liverpool camp. 

Team-mate Virgil van Dijk has moved to play down fears about the forward's happiness, insisting he does not deserve to be attracting negativity. 

"He’s scoring goals. He’s smiling. He can’t smile every second of the day but he’s enjoying it I think," Van Dijk is quoted by the Daily Mail.

"He’s scoring his goals, he’s working hard, defensively as well. We don’t need to see any negative things about that (goal celebration) so we just need to focus on the good things."

It was always unlikely that Salah would be able to replicate his exploits in the 2017/18 campaign in which he scored a total of 44 goals and won the PFA Player of the Year, as well as the Premier League Golden Boot.  

However, Van Dijk believes that the former Roma star is still making a huge contribution. 

"He scored a hat-trick in his last league game and again against Napoli, a very important one. He’s been doing very well," the Dutchman added. 

"People can say he’s not scoring as much goals as last year, but that’s always the media.

"People underestimate how strong he is. He's a very important player, great guy and is deadly in the box."

Surely it will be very difficult for Salah to contain himself should he find the net against Manchester United - and perhaps most importantly, his old critic Jose Mourinho - on Sunday afternoon.  

Why do you think Salah hasn't been celebrating? Have your say in the comments.