Pete Sampras puts his struggles against Barry Cowan behind him with an imperious win over Sargis Sargsian.

Victory also saw the defending champion match Rod Laver's run of 31 unbeaten games at SW19, a feat only bettered by Bjorn Borg with 41.

And the 6-4 6-4 7-5 win was a far cry from the drama Sampras endured in his previous match against Britain's Barry Cowan.

Afterwards, Sampras played down that match as a slight hiccup aware that the real challenges lie ahead in the second week.

"I never thought I was off track," the number one seed added.

Never under anything like the kind of pressure he faced in five-set thriller against Cowan, Sampras even took time to indulge in a spot of rare jocularity.

When a tennis ball became lodged in his shorts, a laughing Sampras rolled them up and invited a ballboy to recover it.

"I said it was all his, he can pick up the ball if he wants. He declined. I guess he didn't want to go up my shorts.

"It was a funny moment and I didn't want to let it slip away - take advantage of that personality I have," he said, in a dig at those who say he is tennis' Mr Boring.

But Sampras said he was proud of his ice cool demeanour, modelled on Bjorn Borg, the player reputed to have ice in his veins.

"In everything I am trying to do I am digging deep but I really don't show it outwardly.

"There are certain tense moments when I will show emotion but as far as losing my cool goes, I've always tried to keep that in check.

"When I was a young spoiled brat I threw my racket occasionally, but my parents were strict on me and I learned at a young age not to lose my cool."

The American never looked anything but calmness personified and a single break in each set proved enough to carry him to victory over his Armenian opponent.

Sampras will now meet Roger Federer of Switzerland, the number 15 seed.