Alastair Cook’s long Test career has been more about tenacity than flamboyance, a quality needed to survive in the first place for anyone taking up the job of seeing off the new ball in seaming English conditions and setting the platform for the rest of the batsmen.It was in evidence since a youngster was flown in from the Caribbean to make his Test debut against India at Nagpur, as injury replacement for Michael Vaughan, in March 2006. A 60 and 104 not out followed. England’s fortunes have been tied to the left-handed batsman’s grit since then and on Monday Cook signed off in perfect fashion, with a century in his final Test innings against India at The Oval.On Monday afternoon, Cook walked off to a grand ovation after playing one such innings for the last time, shaking the hands of each India players and then turning around to acknowledge the crowd before climbing the steps to the dressing room with the applause still ringing. Appropriately, it was debutant Hanuma Vihari bowling his off-spin who had him caught behind for 147, after skipper Joe Root holed him to square leg the previous delivery. One measure of a great Test batsman is a career average of 50; A rare double – Cook is only the fifth to score a century on debut and last Test and owns the England records for most caps, runs and centuries – took his average to only around 45. It shows how demanding his job has been against the moving ball under often overcast skies – more ideal for a visiting bowler to lower his average.Cook, a choirboy before cricket took over, has been happy playing soothing strains, off the limelight reserved more for stroke players in the game. In a sense, the five runs that resulted from Jasprit Bumrah’s overthrows – no four or six -- to get him to his century was in keeping with his self-effacing nature.The unbridled cheering for arguably England’s greatest batsman – there was prolonged, standing ovation by the Oval crowd with players from both sides joining in and his family watching from the stands when he reached his century. It culminated a week in which Cook has been dragged into centre stage since announcing his retirement.Unusual publicity has included his travel on the tube to the ground and comments that he would like to mend fences with Kevin Pietersen. The sacking of KP in 2014 blighted his captaincy although Cook has clarified the final decision was not his. Cook’s legacy as a batsman is immense. Unlike other countries, England have great respect for dour opening batsmen as they acknowledge how difficult it is to find a durable player for the slot.He scored three centuries to achieve the 2012-13 series win in India, rallying after losing the first Test with Pietersen’s great century in the second Test at Wankhede turning this around in terms of batting. That came during his most prolific phase, after his double century, two centuries and two fifties set up the 2010-11 Ashes series victory.As the England camp willed Cook to sign off with a century, they also acknowledged the vacuum he will leave in the opening department. How barren the cupboard is can be gauged from England assistant coach Paul Farbrace saying the struggling Keaton Jennings will be retained for the upcoming Sri Lanka series.