While Dale Steyn put on an exhibition of seam bowling in Galle, the Proteas need their spinners to make more of a contribution in the decisive Test in Colombo.

Steyn finished the match in Galle with a haul of 9-99, but if one is to isolate the spell that swung the Test in South Africa’s favour, it was the period just after tea on Day 3.

Steyn was bowling at 145kph, and getting the ball to reverse. He claimed three scalps, and it was a performance that stalled Sri Lanka’s march on South Africa’s first innings total of 455.

Steyn, and indeed the South African seam attack, was the difference in Galle. Steyn and Morné Morkel claimed 16 of the 20 Sri Lankan wickets. The spinners, JP Duminy and Imran Tahir, could only manage four between them in conditions that favoured the slow bowlers.

How different the result may have been if not for that inspired spell of seam bowling. Indeed, how impotent the Proteas would have proved if not for the presence of the most skilled quick bowler on the planet.

There was a moment in the recent Test when new skipper Hashim Amla was forced to contemplate the scenario. Steyn took a blow to his bowling hand when fielding a ball in the outfield, the same hand he had injured in the recent ODI series. Steyn left the field immediately to have the hand treated. South Africa were fortunate that he was able to return.

The Proteas have relied so heavily on Steyn in recent times. When he has fired, they have rarely lost. When he has been forced to leave the field or has struggled with illness, the bowling attack has not been as effective.

The most recent series against Australia is a case in point. Steyn was battling flu on the eve of that first Test, and while he was subsequently cleared to play, he failed to provide his team with the necessary impetus. Nobody else stepped up to assume the responsibility.

He produced something special in the second Test, helping the Proteas to a resounding win with a day to spare. Unfortunately for the hosts, Steyn was forced to leave the field in the third and decisive Test after just 10.1 overs due to a hamstring injury. South Africa went on to lose that match and their first series in five years.

Steyn has been more than South Africa’s most prolific wicket-taker over the past five seasons. Bowlers such as Morkel and Vernon Philander, who was briefly the ICC’s No 1-ranked Test bowler during the 2013-14 season, have so often taken their cues from the man with the crazy eyes.

The Proteas are on the verge of their first series win in Sri Lanka since 1993. Amla’s charges became the first South Africa team to win in Galle this past Sunday, but the job is only half done. They need to win or draw in Colombo in order to clinch the series.

Is it fair to expect a similarly potent performance from Steyn in the second Test? Indeed, he has proved himself capable of extraordinary feats regardless of the conditions, but perhaps it’s time to ask the question: Does South Africa rely too heavily on their premier strike bowler? And on pitches where spinners should be thriving, is it good enough that Duminy and Tahir contribute a mere 20% of the wickets?

Duminy has developed into a useful option for the Proteas, but is primarily a batsman. Tahir, on the other hand, has no excuse for failing to hit the right line and length on a consistent basis.

It was hoped that South Africa’s sole leg-spinning option would settle, that he would develop over time and contribute in seam-friendly conditions. It was hoped that he would dominate on the dust bowls of the subcontinent, troubling the top order and then making quick work of the tail-enders. Sadly, Tahir has proved a failure on all counts.

The memory of the 2012 tour to Australia, where Tahir was carted to all corners by the hosts, is still relatively fresh. And now on his first tour with South Africa to Sri Lanka, Tahir is battling with the basics.

The Proteas so desperately want a world-class slow bowler to complement Steyn and company, but the time may have arrived to explore other options. A quality leg-spinner would certainly add another dimension to the attack. What’s become clear is that Tahir is never going to fulfil that role, and persisting with him in the Test side is delaying the process of finding a player who can.