Quinton de Kock's outstanding Test run

Over the next six weeks, South Africa will look to right what has so far been a pretty disappointing tour to England for all their teams: they lost the ODI series and the T20I series by 2-1 margins, were knocked out disappointingly early in the Champions Trophy, while the A team was thrashed by England in the one-off Test and the three-match one-day series.

Going into the Tests, South Africa already have plenty going against them, apart from the above results: AB de Villiers' future is uncertain, and Faf du Plessis might miss the first Test, as might coach Russell Domingo. What they do have in their favour is the form of Quinton de Kock, the wicketkeeper-batsman whose exploits in both Tests and ODIs have been some of the brightest bits for South Africa over the last 18 months. Since the beginning of 2016, de Kock averages 59.38 from 13 Tests, and 49.22 from 32 ODIs. In the six ODIs he has played in England this season, he has got starts in all but one, notching up scores of 5, 98, 34, 23, 33, and 53.

His Test form over the last 18 months has been even more encouraging: in 21 innings he has passed 50 ten times, including three hundreds and four other scores between 80 and 99.

These are still fairly early days in de Kock's Test career, but his numbers at this stage are pretty similar to those of another wicketkeeper who used to bat left-handed, and used to hit the ball a fair distance. After 19 Tests, de Kock has scored 1333 runs at an average of 51.26 and a strike rate of 71.58; after 19 Tests, Adam Gilchrist had scored 1236 runs, averaging 53.73 at a strike rate of 78.27. The number of 50-plus scores are pretty similar as well.

In the last 18 months, de Kock has averaged nearly 60 in 21 Test innings, numbers that put him right up with the best batsmen during this period: among those who have scored 1000-plus runs during this period, his average is next only to those of Steven Smith, Virat Kohli and Cheteshwar Pujara, and ahead of Kane Williamson (55.50), Joe Root (49.23) and David Warner (39.60). De Kock's feat of getting to 1000 Test runs in 23 innings has been bettered by only four South Africans: Graeme Smith (17), de Villiers (20), Eddie Barlow (21) and Graeme Pollock (22). Du Plessis has also got there in 23.

Among the top five in that list are the two wicketkeeper-batsmen who will be key members of their teams in the England-South Africa series. Jonny Bairstow has been as impressive as de Kock during this period, averaging 58.80 in the 17 Tests he played in 2016. England haven't yet played a Test in 2017, but that hasn't stopped Bairstow from scoring runs in other formats this season: in his last four international innings he has notched up scores of 51 (ODI v South Africa), 43 (ODI v Pakistan), 60 not out and 47 (T20Is v South Africa). Earlier in the season, he also scored a List A career best of 174 for Yorkshire versus Durham.

Bairstow and de Kock are also two of only four wicketkeeper-batsmen in Test history who have scored 1000-plus runs at 50-plus averages - the others are de Villiers and Andy Flower. (Gilchrist had a 50-plus average for much of his Test career, but a poor run towards the end meant he had to settle for a career average of 47.60.) The clash of the two wicketkeeper-batsmen could be a key battle in the upcoming series, and the runs they score could also hugely impact the lower-order contribution of each team.

Wicketkeepers with 1000-plus runs and 50-plus averages

Player	Mat*	Inns	Runs	Ave	100s	50s
AB de Villiers	24	39	2067	57.41	7	7
Quinton de Kock	18	28	1292	53.83	3	9
Andy Flower	55	100	4404	53.70	12	23
Jonny Bairstow	21	37	1682	50.96	3	9

* Tests in which they have kept wicket

De Kock's contributions in the series will also be key, as the South African top order isn't in top shape. De Villiers is missing, and du Plessis might miss the first Test. Hashim Amla averages a healthy 45.43 in Tests since the start of 2016, but he had a fairly ordinary tour of New Zealand earlier this year, scoring 153 runs in six innings. Also, Dean Elgar JP Duminy and Temba Bavuma all average less than 40 in this period (though Elgar only misses the mark marginally). Given that these batsmen will be up against a top-class England pace attack in conditions that could favour seam and swing, de Kock's contributions at No. 7, and his ability to play momentum-changing innings, could have a huge impact on South Africa's fortunes in the series.