Zak Crawley and Dom Sibley shared England’s first century opening stand since December 2016 on day one against South Africa in Johannesburg.
England cycled through Jennings, Mark Stoneman, Joe Denly and Jason Roy before settling on Rory Burns and Sibley as an opening pair, with a stand of 92 in the first Test against the Proteas offering early reward.
Crawley replaced the injured Burns midway through the current series and he and Sibley put on 70 in Port Elizabeth before ending the drought with 107 at the Wanderers.
Cook and Jennings, despite their success in Chennai and their 99 in the previous Test in Mumbai, averaged only 32.40 as a pair before England’s long search for a partner for their former captain landed on Stoneman.
In 20 innings together, the pair passed 50 only twice and had a best of 58, averaging just 18.75 as a partnership.
Cook retired and Stoneman was dropped, leaving Burns and the recalled Jennings to start the new era – their average stand of 29.33 was an improvement but did not come close to providing an answer.
Disregarding Jack Leach’s two innings as a nightwatchman opener, Joe Denly was next to get his chance at the top of the order but after moving up from the middle order, he and Burns averaged only 21.67 together.
A short-lived experiment with one-day specialist Jason Roy yielded only seven partnerships with Burns, and 83 total runs, before Sibley joined Burns in a seemingly more reliable union. They passed 50 twice in five innings before Burns was sidelined, with Sibley not missing a beat alongside Crawley.
As if to illustrate the churn at the top of the order, England’s previous eight century opening stands featured Cook with eight different partners – Jennings, Haseeb Hameed, Ben Duckett, Alex Hales, Moeen Ali, Adam Lyth, Jonathan Trott and Nick Compton.
Cook and Compton were the last England opening pair to pass 100 on more than one occasion, doing so three times in 17 innings with an average stand together of 57.93.
The latter figure is only bettered by Cook and Hameed since then – their five partnerships, before injury and a subsequent loss of form took the youngster out of the picture, yielded an average of 67.60.