Hampshire 131 for 7 (Vince 62, Bamber 3-41, Murtagh 2-16) trail Middlesex 172 (Gubbins 51, Abbott 6-44) by 41 runs
With three wickets on the first evening, Kyle Abbott felt he'd found his rhythm for the first time this season. By halfway through the second day, he'd slayed his gig at Lord's with a haul of six to bowl Middlesex out for just 172.
But then the Middlesex bowlers got in on the act and ripped that to shreds as Hampshire, who slumped to 9 for 3 at one stage, closed at 131 for 7 in reply on a day when 13 wickets fell in total.
James Vince's fighting half-century, which included a partnership worth 54 with Keith Barker, kept Hampshire in the contest, just.
At the close, Barker, who scored an unbeaten 52 in a losing cause against Somerset last week, was not out on 23 with Abbott yet to score after Ethan Bamber and Tim Murtagh had claimed five wickets between them to dig Middlesex out of a hole.
Bamber had impact from the outset, bowling Ian Holland for a duck with a gem that angled in slightly and crashed into off-stump.
He then had Joe Weatherley out edging to Martin Andersson at third slip and, next ball, Murtagh dismissed Tom Alsop lbw to put Hampshire in terrible trouble inside seven overs.
It looked like it would come down to the experienced duo of Sam Northeast and Vince, their captain, to steady the visitors but when James Harris trapped Northeast clearly lbw, they were seriously struggling.
Vince and Liam Dawson returned from tea with their side 47 for 4 but they were unable to form the big partnership that was so desperately needed, with Dawson caught by a leaping first slip Robbie White as Murtagh claimed his second wicket.
With Lewis McManus going cheaply and unarguably lbw to Bamber, Vince continued to build a tenacious innings with Barker in support. But then 19-year-old Blake Cullen tempted Vince into a missed drive and pegged back his off-stump with a fuller ball that nipped back a little to end his knock on 62.
"It was a hard day for batting, it felt really tough out there," Vince said. "It got a little bit easier as the ball got softer but there was always something happening. The ball is taking some divots out where there is still grass on the pitch.
"I think I used every part of the bat out there with some of them even coming off the back. I rode my luck a bit and tried to strike a balance between trying to hang in there until the ball got a bit softer but trying to score runs as well."
Mohammad Abbas provided excellent backing for Abbott after bowling well for no reward on a rain-affected first evening, as he claimed the other three Middlesex wickets to fall on the second day.
Abbott struck in the third over when he had John Simpson out lbw with a ball that pitched on off-stump and struck the knee-roll in line with middle, with the hosts having added just one run to their overnight score of 90 for 4.
Andersson brought up Middlesex's hundred with a lovely square drive to the boundary off Abbas, just moments before he was floored by a delivery from the same bowler hitting him in the groin. By the time he made it back onto his feet some minutes later and still in obvious pain, play was halted for bad light with just half an hour of the morning session gone, the stricken batsman no doubt thankful.
After a delay of 15 minutes, the players returned to the field, Andersson among them but ever so briefly, facing just one ball before he fell lbw in an Abbas double-strike which also claimed Andersson's replacement, Harris, who was bowled for a second-ball duck.
With the floodlights on but the overcast sky still brighter and much drier than the previous day when the start was pushed back until 4.15pm, the temperature remained far too frigid for mid-May.
Gubbins gritted out his fourth half-century of the season and will have some bruises to show for it after being struck on the left thumb by an Abbott delivery that spat up off a length, before wearing a Brad Wheal ball painfully on his left hip.
Gubbins threw a few punches himself, a finely struck four off Abbott through point followed by two off Wheal, square of the wicket on either side. But, after adding just one more run after lunch, Gubbins fell to Abbas's great line and length, deciding late to leave and deflecting the ball onto his stumps.
Abbott claimed his five-for when Cullen, who had faced 77 balls for his 27, prodded at a length ball outside off and found Vince at first slip. Abbott then wrapped up the innings with his sixth, an excellent delivery on middle stump which struck Bamber low on the pad, directly in front.
Valkerie Baynes is a general editor at ESPNcricinfo