Ryan Sidebottom and Harris had already taken a wicket each when Pietersen came to the crease for his first appearance at Trent Bridge since leaving Notts for the south coast in the winter.
His innings proved a brief one, as he was adjudged lbw to his second ball, with Harris going on to add the wickets of Craig McMillan, Nic Pothas and Sean Ervine before the close.
After a delay for rain, the eagerly-anticipated match between first and second in the table began at 12.30pm as Hampshire won the toss and chose to bat.
But our good bowling under cloudy skies kept the pressure on the visitors, who had reached 222-7 when bad light ended play.
THURSDAY 21 SEPTEMBER 2017
ENGLAND v WEST INDIES