FOUR in a row now and no sign of letting up.

Having collected the consecutive set of major titles - the so-called Serena Slam - Serena Williams will aim to complete the calendar-year Grand Slam at the US Open.

After that, the target is Margaret Court's record of six straight Grand Slams. And on the form Williams showed in beating Garbine Muguruza 6-4, 6-4 to win her sixth Wimbledon final yesterday, the only woman likely to stop the world No 1 from equalling the Australian's feat is herself.

It is remarkable enough that the 33-year-old has now won 21 Grand Slams, but the reality is that she could easily have won a handful more, and by now gone clear of Court's record haul of 24.

Injury, nerves and even boredom have played a greater role in reducing the American's total of titles than anyone else, with the possible exception of her older sister Venus.

Presuming Serena keeps on playing for the next couple of years at least, Muguruza and Madison Keys should mature enough to be able to beat her on the big occasion. This time, though, the best the No 20 seed from Spain could do in her first major final was to keep the contest competitive.

On the eve of the match, Muguruza had shrugged off the suggestion that she would crumble on the big occasion by stating that Williams was likely to be just as nervous as her.

She was proven correct, too, as the older woman had a dreadful first game, double-faulting twice on her way to being broken.

Muguruza remained on top until Williams broke back to level at 4-4, and after that there was a sense of inevitability as the top seed broke again to take the set.

As had been the case for Andy Murray when up against Roger Federer 24 hours earlier, Muguruza was doing little wrong: she simply had to accept that her opponent was superior in just about every aspect of the match.

Williams' first serve was 10 miles an hour quicker than the Spaniard's, and her ground strokes that little bit harder.

As a result, Muguruza looked leaden-footed at times as she failed to chase down shots to the corners, which was an apparent contrast to the athleticism she had shown in knocking out four more highly ranked seeds en route to the final.

But the reason for that, quite simply, is that Williams is a tougher opponent by far than those other women - and, indeed, than almost everyone else who has ever played the game.

Having taken control of the match, the favourite was in no mood to relinquish it as the second set got under way. The ace with which she began it was testament to that - although her rhythm was still off at times, leading to a few embarrassing double faults.

Even so, Muguruza continued to feel the pressure, and when she was broken to go 3-1 behind, her defeat looked to be just a few games away.

That was all the more the case when Williams broke again to take a 5-1 lead, but then, with nothing at all to lose, Muguruza played some of her best tennis of the match.

Sensing that Williams would become nervous when serving for the championship, the Spaniard went on the offensive in the seventh game, winning it with some excellent ground strokes.

Another hold for 5-3, and then she broke Williams again, in a game which saw her best shot of the match, a cross-court winner which left her opponent stretching desperately.

But then, having played in such uninhibited style when the pressure was off, Muguruza tightened up when forced to serve to stay in the match for a second time at 5-4 down. A double fault cost her the first point, a net cord the second and an unforced error the third, and then the dream was over - at least for now.

When they met at the net at the end, Williams told her beaten opponent that she would be winning this title in a couple of years. It is a prediction that appears certain to be fulfilled, but for the time being neither Muguruza nor anyone else can live with the great American when she puts her mind to it.