As New Zealand resumed last night on the third day of the final Test match against England in a weaker position than they had on the second, Stephen Fleming would have been well aware that he needed to score a fair few more than 54 runs in his second innings to save the game.

However, 54 was the minimum target for the former New Zealand captain if he was to end the last of his 111 Test matches with a career batting average of more than 40, the conventional benchmark of a fine batsman.

History did not give Fleming much reason for optimism; time and again, batsmen have stumbled when in sight of a statistical landmark. Don Bradman was the most notable. Needing four runs in his final Test innings at the Oval in 1948 to finish his career with an average of 100 - and just one boundary away from being the first Australian to score 7,000 Test runs - he was bowled second ball for a duck.

Yet Bradman's tally of 6,996 runs and his average of 99.94 are like a freckle on the face of a Hollywood starlet: the imperfection only draws your attention closer to the rare beauty.

Eddie Paynter was another who failed in his final challenge in 1939. Needing to score 29 runs in two innings to finish his career with an average of 60 - beaten by only four men in Test history - the Lancastrian scored nine and nought. Likewise last year, Inzamam-ul-Haq, the Pakistan captain, was stumped off his second ball in his final innings, needing four more runs to become his country's highest run-scorer. In the process, his career average also dipped below 50.

If the number of runs that Fleming requires for his own statistical curio is a bit greater than those three, the achievement is rather less.

Although 40 remains the benchmark for modern batsmen, it is a base camp rather than a peak. Fleming's present average of 39.92 places him only 59th in a list of batsmen to have played at least ten Tests since he made his Test debut in 1994. His career has slowly improved - since 2000 he averages more than 41, but that still only squeezes him into the top 50 so far this century.

In these days of better pitches, inferior bowlers in general and opportunities to massage an average against Bangladesh and Zimbabwe, it is little wonder that 50 is seen as the new 40. Nineteen batsmen have averaged more than 50 since 2000 and a further 12 average more than 45. Mike Hussey, the Australia batsman, is averaging almost 80 after 22 Tests. A little more than 7 per cent of the batsmen who have played more than ten Tests since 2000 average more than 50, which makes the present decade the best for high-scoring since the 1940s, truncated by war. The 1920s and 1930s also featured a high percentage of batsmen averaging more than 50.

With typical contrariness, England's standards have been heading downwards of late. At the end of the 2006 summer, England had four playing batsmen averaging more than 45 and a further three between 40 and 45 (plus Owais Shah, who had scored 126 runs in his only Test). Of the XI playing in Napier today, the top six still average above 40, but only Kevin Pietersen is averaging more than 44. Andrew Strauss, whose average was more than 50 after the 2005 Ashes series, now averages 40.02.

Compared with his compatriots, Fleming is almost a giant. Only six New Zealanders have ended their career with an average of 40, the best of them John Reid (46.28). Yet while Fleming's haul of 54 Test innings of more than 50 is far greater than the next best (Martin Crowe, John Wright and Nathan Astle all did it 35 times), he has made only nine hundreds, suggesting an unfulfilled talent.

The second innings in Napier would be an ideal time to make his tenth. In doing so, Fleming would end his career on perhaps the biggest high since Greg Chappell started his final Test needing 69 to go past Bradman's Australia record and made 182.