Bates, 34, the former British No 1 and winner of this title six times, retired from serious tournament play after Wimbledon this year but most people still expected him to beat Robinson even though he insists he is "playing only for fun" this week.
Robinson, who had beaten the fourth-seeded Danny Sapsford in the first round, was always in control, breaking Bates' service twice in each set and losing his own just once in the match.
Robinson won the first set in 29 minutes after three successive breaks had left him leading 3-2 with his service to follow and then won the second set in 30 minutes with breaks in the fifth and ninth games to move into the quarter-finals.
Bates is shortly to take over as manager for national training at the Lawn Tennis Association and Robinson said: "It did cross my mind that I was playing the boss but Leighton Alfred, my coach, said it would do me a lot of good if I played well. I had never played Jeremy before but I have a lot of respect for him because he was our top player for so long. But I told myself not to think about that.''
Greg Rusedski, the British No 2, survived a difficult match, having his service broken twice by Miles Maclagan, the West of Scotland player, in the opening set to trail 5-2. But he won the next four games to lead 6- 5. Maclagan then held serve to force a tie-break but Rusedski won it 7- 1 and eventually the match 7-6, 6-4.
Samantha Smith, the British women's No 1 had a terrible day, losing her quarter-final match with Claire Taylor 4-6, 6-3, 6-4 before being criticised by LTA officials for speaking out about the state of the British game.Reuse content