Jeremy Corbyn faced what should have been an open goal. Six times he ran up and kicked the ball towards it. We congratulate him for getting his shots on target: six times he asked David Cameron to guarantee that “nobody will be worse off next year as a result of cuts to tax credits”.

But Corbyn as a striker lacks penetrative power. His shots were not just predictable: they were so slow the keeper had no difficulty gathering them and kicking the ball back upfield.

And Corbyn is having trouble with the crowd. Instead of imposing himself, he waits in vain for silence, and conducts himself like a huffy geography teacher who wonders what the world is coming to when it won’t treat with respect his fascinating account of glaciation.

The way to silence that crowd of hooligans is to shoot goals past Cameron by being quicker, wittier and more ruthless. Of those dangerous qualities, Corbyn betrays no sign. He is, in fact, a pretty feeble champion of his own cause, who does not raise the morale of his own side by defeating the enemy.

It is of course possible that the enemy will defeat itself. George Osborne has just scored an own goal with the tax credits fiasco. But Corbyn was unable to exploit this gift by scoring any goals of his own. The Tories were instead even keener than usual to show their support for the Prime Minister.

Stephen Metcalfe (Con, South Basildon and East Thurrock) pointed out that “one in ten of the world’s tractors are built in Basildon”. This gave Cameron the chance to say that Corbyn, whose “new spokesman is an admirer of the Soviet Union”, will doubtless be “very pleased to start the day with tractor statistics”.

Graham Evans (Con, Weaver Vale) said he had received an email from John, in Weaver Vale, who is delighted that the Tories have stuck to “Our Long-Term Economic Plan”, known to this column as Oltep. Good old Oltep, always there when you need him.

And here was Boris Johnson (Con, Uxbridge and South Ruislip), not always there when you need him, but today beaming and nodding and sitting on the front bench below the gangway, so somewhat nearer to the Dispatch Box than normal. He has without doubt been perked up by Osborne’s own goal.

Cameron went out of his way to be unkind to Tim Farron, the Liberal Democrat leader, telling him it was “good to see such a high turnout of his MPs”. Since Farron now has only seven MPs apart from himself, and not all of them were there (we looked in vain for his predecessor, Nick Clegg), this was a cruel observation.

But the jibe was much enjoyed by the Conservatives, and was also, perhaps, a way of reminding people that Cameron, by being so kind to the Lib Dems during the last Parliament, has pretty much killed them off. Here is a Prime Minister who does not lack ruthlessness.

Rupa Huq (Lab, Ealing Central and Acton) asked the Prime Minister if he is a feminist. If feminism means treating people equally, he responded, then “yes, absolutely”. But Corbyn shows no sign of being able to get on terms of equality with the Prime Minister.

No doubt Cameron, like Osborne, will occasionally fumble the ball into his own net. But for those of us who would like to see PMQs as a sporting contest which is exciting because one cannot tell from week to week who is going to win, Corbyn has so far proved a bit of a wash-out.