Runs are key in the debate over Alastair Cook's England captaincy

Cook is a leader who is successful when he can set an example through deeds rather than words

A captain does not need to make inspirational bowling changes. He can survive without setting an unorthodox field that brings a wicket. Sometimes, all that is required is for him to do his job better than anyone else.

Once more, Alastair Cook’s leadership suffered serious scrutiny as Sri Lanka moved into a dominant position. Some of his tactics today, when visiting captain Angelo Mathews and Rangana Herath were batting together, were hard to understand.

Little faith was shown in the off-spin of Moeen Ali, even though he finished day three with figures of two for 32 from his 10 overs. As soon as Herath, a tailender, walked to the crease, England seemed to abandon any plans they had to take Mathews’ wicket.

As a tactician, Mathews is no Brendon McCullum, nor Michael Clarke. Indeed, some of his on-field calls appear to be questioned openly by Mahela Jayawardene, a former skipper. Jayawardene cannot, however, challenge Mathews’ contribution as a cricketer.

After a century in the First Investec Test at Lord’s, coupled with an obdurate effort in the second innings that helped Sri Lanka hang on for a draw, Mathews has excelled here.

He collected four for 44 in England’s first innings before producing one of the knocks of his career in the second. Mathews’ 160, made in five hours and nine minutes, was a work of art. He knew when to accelerate, when to sit tight, how to take the fight to the bowlers and how to manage Herath, a lower-order batsman with a sound enough technique.

But Herath should not be hanging around as long as he did to make 48 in a stand of 149 with his captain. When you can affect a match like that, who cares about funky fields? Mathews is the team’s all-rounder, and his work with both bat and ball in this game has been peerless.

Mathews’ brilliant hundred does not make him a better captain, no more than does his superbly intelligent spell of medium-pace bowling that finished off England’s lower order on Saturday morning. It does bolster his authority, though, and gives him far more latitude than he would have if he were in poor form.

Has Cook become a worse captain since he took the Test job in 2012 and led the team to victory in India, scoring three centuries in the series? Of course not. Like Mathews, Cook is a leader who is successful when he can set an example through deeds rather than words.

If runs start to flow for him again, he will be shown more patience. If the lean streak continues, and his late dismissal last night hardly helped his cause, Cook may find it difficult to see out the summer.

The principal candidate to replace him would be Ian Bell, but Graeme Swann, a team-mate of both men, believes Cook is more naturally suited to the role.

“Alastair Cook is the right man to lead the team,” Swann told BBC Test Match Special. “I don’t think Ian Bell has got the personality and I think Cook is more of a leader than Ian Bell.

“Alastair Cook just needs to score runs. That would get a huge monkey off his back,” said Swann. “If you’re a genuine England fan you should get behind Alastair Cook and hope he and [coach] Peter Moores show us the fresh brand of cricket they’re bringing.”