The Stormers maintained their 100 per cent Super Rugby record by grinding out a 17-7 victory over the Jaguares at a rainy Newlands before the Blues snatched a last-gasp win over the Bulls.

It was not pretty, but the leaders outmuscled their Argentinian opponents to make it four wins out of four and go three points clear of defending champions the Crusaders as the only unbeaten side.

A Damian Willemse penalty was the only score of the first half on a miserable day in Cape Town, but Herschel Jantjies scooped up a loose ball to go over for the opening try five minutes after the break.

Willemse laid on a second try for Ruhan Nel, with the fly-half making no mistake with his conversion attempt to ensure Rodrigo Bruni's try was no more than a consolation for Gonzalo Quesada's men.

The Bulls were on the verge of their first win of the season but Otere Black's penalty right at the end gave the Blues a 23-21 triumph.

Morne Steyn scored the Bulls' first try of the season and another from Jeandre Rudolph put them on course for victory, but Black denied them right at the end.

Mark Telea, Tom Robinson and Stephen Perofeta were the try-scorers for the Blues, who now have two wins from four matches.