She lost the final of the Australian Open to Angelique Kerber and the final of the French Open to Garbine Muguruza, but as Serena Williams continues her pursuit of another major milestone the biggest obstacle may be an opponent she last met 17 years ago.

No disrespect is intended towards either Kerber or Muguruza but there was little evidence during the first three Grand Slams of 2015 that either they or, for that matter, Roberta Vinci who beat the American in the semi-final of last season’s US Open, were likely to represent much in the way of threat to her prospects of matching Steffi Graf’s open era record of 22 Grand Slam wins.

Instead the suspicion has to be that the magnitude of that achievement, given the position Graf held in the sport when Serena and older sister Venus were emerging in the professional game in the late nineties, has been something of a psychological barrier and all the more so now she is on the brink of it.

As impressive as the younger Williams has been down the years it is not that difficult to understand why.

No-one in the modern game can possibly understand just what it took for the German woman to produce such consistency over an intense period before retiring when still aged only 30 than this opponent who, before embarking on her own pursuit of greatness, faced her just twice, both of them winning one three set encounter apiece.

Graf claimed her first Grand Slam win when, just as she was turning 18, she showed extraordinary courage to win a final set decider 8-6 at the 1987 French Open against the still dominant Martina Navratilova who would go on to win that year’s Wimbledon and US Open. Those proved the great Czech-born, adopted American’s last Grand Slam successes, however, because Graf then embarked on a run that is unlikely to come close to being matched.

Whereas Margaret Court, who straddled the amateur and open eras, took 14 seasons to acquire her 24 Grand Slam titles, Graf would win all bar one more of her 22 in a nine season burst of dominance which meant that beginning that sequence with her ‘Golden Slam’ which saw her win all four Grand Slams plus the Olympic title in the same season, she won well over half the available titles between the beginning of 1988 and the end of 1996.

Thereafter she would lift herself just that once more, at the 1999 French Open, before finally succumbing to injury later that season, but having often battled with motivation down the years, at times almost seeming bored with the sport, Serena Williams surely knows just what that took and must therefore consider Graf with comparable awe to the way she is looked at by her own contemporaries.

Neither Williams sister had won a Grand Slam title before Graf retired, Serena claiming the US Open immediately afterwards while Venus was to win the first of their combined 11 Wimbledon titles the following year, but it has taken 17 years to get this close to achieving what Graf did in so much shorter order.

A further clue that Serena might be feeling the weight of history came when, up against one of Graf’s German compatriots in Kerber, she lost the deciding set of a Grand Slam final for the first time in her career.

Yet if she is to match Graf’s record then where better for the 34-year-old to do it than on the centre court that was her great predecessor’s favourite place to play? No Grand Slam champion has proven their all-court game as effectively as Graf did, standing alone as she does in having won at least four titles at each of the four venues, however her seven wins at Wimbledon, as compared with six in Paris, five at the US Open and four in Australia, made it the venue with which she is most associated.

Serena also stands to match that haul of seven Wimbledon wins with victory this time and, surprisingly fallible as she may have become since she won her last Grand Slam title here a year ago, the defending champion will again rightly be the strongest of favourites. She may, too, find that at her advancing age this surface gives her the best chance of preventing younger opponents from exposing any hitherto unsuspected vulnerability to attrition.

The way Muguruza beat her in Paris earlier this month has seen the Spanish 22-year-old tipped to win many more Grand Slam tournaments and she is seeded to reach this final too. However when it comes to psychological barriers it is worth noting that there were close to two years between Williams’ first and second Grand Slam wins, a full year separated those of Martina Navratilova, Billie Jean King and Margaret Court and even the mighty Graf missed out on those two at the end of 1987 before claiming her second, third, fourth, fifth, sixth, seventh, eighth and ninth in the space of the next nine available.

As we saw at the US Open last year and at this season’s Australian Open, a combination of age and pressure mean that the danger to Williams could manifest itself in unlikely fashion. Things always change when the fear factor that is part of every great champion’s weaponry is undermined and on a given day any one of a number of bright young things may now believe they can get lucky if they are prepared to go for their shots from the off and keep gambling if they do get the upper hand.

As a consequence it may even be now or never for Williams and realisation of that could have the effect of shackling her even more or liberating her… perhaps both at different points in the coming fortnight.

It may well be, too, that winning that 22nd Grand Slam title could provide the platform from which Williams can go on to set new standards first in the open era and then in the history of the sport, but the overall effect of all of that is to ensure that there is more interest in the women’s singles at Wimbledon 2016 than there has been for many years.