Three early wickets for a fired up Steven Patterson helped Yorkshire take a grip of their LV= County Championship match against Middlesex at Headingley in an encounter that could determine which side takes second place in the Division One table.
Bowled out for 210 on a seaming and swinging pitch, the White Rose hit back to dismiss their opponents for 128 and gain a first-innings lead of 82, which they had extended to 86 by the end of the second day when reaching four without loss.
Ryan Sidebottom did much of the later damage to finish up with four wickets while Patterson and Jack Brooks had three apiece.
It was a remarkable day for both wicketkeepers with John Simpson holding on to six catches - a record for Middlesex against Yorkshire - before Jonny Bairstow emulated the feat.
Bairstow's six were joint-second in the club’s history with only his father, David, having taken seven - against Derbyshire at Scarborough in 1982.
If Yorkshire either win or draw, they are assured of second place and £235,000 in prize-money whereas Middlesex must win this, their last game of the season, to stay in with a chance of overhauling their opponents.
In his first over, Patterson had Chris Rogers caught at point by Adil Rashid the ball after the Australia Test opener had struck a boundary to reach 1,000 championship runs for the season.
It became 21 for two as Joe Denly was undone by late movement, edging low to Adam Lyth at second slip and Patterson was rested shortly before tea with figures of 2-17 from six overs.
He returned after the interval and another great delivery had Dawid Malan caught behind by Bairstow but Sam Robson continued to go for his shots until nicking Brooks to Bairstow, his 45 coming off 70 deliveries with seven boundaries.
Sidebottom, who had bowled well without reward, then got in on the act as Neil Dexter and Gareth Berg were pouched by Bairstow and, when Simpson fell lbw to Brooks, Middlesex had collapsed to 110 for seven.
Bairstow’s fifth catch sent back Tom Helm, who made contact with a short ball from Brooks and his sixth came when Tim Murtagh flashed wildly at Sidebottom - who rounded off the innings by having Ollie Rayner caught at long-leg.
Yorkshire began the shower-interrupted day on 90 for three and only the stubborn Kane Williamson made any real impact against Middlesex's nagging seamers who took wickets regularly.
The New Zealander took his overnight 34 to 52 in four-and-a-half hours before he was caught by Simpson off debutant Helm, who shortly before had claimed his first championship wicket with the dismissal of Rashid.