Kevin Pietersen marked his return to competitive cricket following a knee injury with an unbeaten century for Surrey on day three of their clash with Yorkshire.
The 32-year-old England international - out of action since he was forced to leave the tour of New Zealand in March due to bone bruising behind his knee - was 177 not out by the time the visitors declared on 353-7 at Headingley.
In proving his fitness ahead of the upcoming Ashes series, Pietersen hit 17 fours and seven sixes in a superb 188-ball knock that was much-needed by his county against the current Division One leaders.
Having fielded for almost 136 overs while the hosts racked up 433-9 over the first two days, he came in on day three with Surrey 62-3 and proceeded to lead a revival, reaching a superb century off just 106 balls.
The right-hander is often over-eager to get off the mark and he could have been run out from his first ball if Adil Rashid's throw had been a little better.
Yorkshire then had a hopeful appeal for caught behind turned down when Pietersen faced Ryan Sidebottom for the first time, but the former Hampshire batsman settled down after that and produced a typically stylish knock.
His century featured 12 boundaries and a pair of sixes, one of them driven back over the head of leg-spinner Rashid, whose bowling Pietersen took a liking too.
He did offer Rashid a very difficult half-chance when on 78 but the bowler could only get a hand to a powerful straight drive. To rub salt in the wounds, he would later take 17 off one over from the leg-spinner.
Pietersen - who was also missed on 120 by Yorkshire wicketkeeper Andrew Hodd off the part-time spin of Adam Lyth - shared partnerships of 97 with Zander de Bruyn (38) and 118 with Steven Davies, who contributed 44.
Yorkshire were left with 21 overs to bat but only lost Alex Lees, who offered no stroke to Gary Keedy and was lbw for 13, as they reached the close on 52-1, meaning a lead of 132 going into the final day of the fixture.