The visitors made an encouraging start and reduced Nottinghamshire to 40 for three early in the day. However, Pietersen and Darren Bicknell (108) forged a 316-run partnership before the hosts closed on a commanding 416 for six.

Having won the toss, Nottinghamshire skipper Jason Gallian decided to bat first - and Guy Welton crashed consecutive shots to the boundary off Aaron Laraman's first over. Welton also took advantage of a short delivery from the Middlesex seamer in the fifth over when he rocked back and hammered the ball through midwicket region. However, it was Laraman who made the first breakthrough when he bowled Gallian, who did not offer a shot.

Bicknell settled immediately and played a delightful late cut to the third man boundary. But the hosts added just four to the score when Welton (24) was dismissed by Chad Keegan. The 23-year-old produced a quick, straight delivery which struck Welton's pad in line.

The dismissal brought Usman Afzaal to the crease, but the left-hander contributed just four runs before he became Laraman's second victim to leave the hosts reeling on 40 for three.

However, Pietersen strode confidently to the crease in the 11th over and took the game to the Middlesex bowlers. He and Bicknell kept the scoreboard ticking over but it was Pietersen who accelerated the scoring. He was particularly unforgiving during one Simon Cook over, scoring 12 runs in boundaries.

Middlesex were becoming increasingly frustrated by the double century stand and they were relieved it was finally broken in the 94th over. Off-spinner Paul Weekes found a way through Bicknell's defence to reduce Nottinghamshire to 356 for four.

Wicketkeeper Chris Read faced only a handful of deliveries before pulling a short ball from Keegan to the mid-wicket boundary. However, he made just 12 before he was clean bowled by Cook - and Paul Johnson (nine) fell just before the close when he was trapped on the crease by Keegan. But Pietersen was still there at the end with Richard Logan, who had progressed to six.

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