Middlesex 321 for 2 (Rogers 173, Denly 105*) lead Somerset 173 by 148 runs

Chris Rogers batted like he had a plane to catch or, more relevantly, a poor weather forecast to defy. In between the showers, Middlesex have so far clambered all over Somerset at Lord's, and Rogers' sparkling 173 matched the visitors' total all on his own. It was compiled with the urgency of a captain who knows he will likely have limited time over the next two days to force a result that could take the hosts to top of the County Championship.

Alongside a nicely modulated 105 not out from Joe Denly, Rogers hurried Middlesex to 321 for 2 by the close, 148 runs clear of Somerset's plainly inadequate 173. Rogers is commonly - and somewhat lazily - regarded as "merely a first-class batsman", the rough and tumble of Twenty20 and some limited overs cricket having passed him by in the eyes of various selection panels. But he was brimful of assertive strokes here, whether punching emphatically through the covers or flicking straighter deliveries through or over midwicket.

He blazed from 62 to 78 with four boundaries in five balls delivered by Gemaal Hussain, and after reaching his century took a mere 28 balls to go to 150, pelting the seats beyond the short eastern boundary with a trio of sixes. Rogers had added 245 with Denly when he perished to Peter Trego's bouncer, caught on the deep backward square leg rope by Arul Suppiah. A weary Somerset were grateful to see stumps drawn at 7pm.

All this took place on the same pitch that had helped Middlesex's bowlers rumble through the remainder of Somerset's batting in the space of 10 balls on the second morning. The burst was made all the more critical by the continued absence of Corey Collymore, who did not bowl again after complaining of knee pain on the first afternoon. Rousing themselves accordingly, Gareth Berg and Tim Murtagh shared the spoils as Craig Kieswetter perished without addition to his 48, Jos Buttler completed a duck of two days' duration, and Craig Overton edged behind first ball.

Murtagh was on a hat-trick at that point, but it was Berg who claimed the fourth wicket of a frenzied passage when he found a way through Alfonso Thomas' forward stroke. Trego salvaged another 40 runs from the remainder of the innings, primarily in a stand of 31 with George Dockrell, before Toby Roland-Jones winkled out the last two.

Robson and Rogers began the Middlesex reply in collected fashion, covering the movement on offer to Trego and Gemaal Hussain. Thomas' introduction had Robson shuffling across the crease and pinned LBW. Joe Denly walked to the wicket with a decent run of scores behind him, and found a more sedate gear in the middle while Rogers accounted for the major share of the scoring up to tea.

There was the sniff of a dropped chance before Denly had scored, and Thomas appealed vehemently for LBW when he had 9, but the umpire Neil Mallender was unmoved. It was to be the last notable moment for Somerset's bowlers in the day. Denly grew into an innings of greater authority and power with every added minute of shared occupation alongside his captain.

Rogers was a little more circumspect in the shadows of his century, working in singles where previously he had dealt in boundaries. By then, however, the momentum was all with Middlesex, and he duly reached his second century of the season and the 54th of his career. The stroke that took him there, an inside edge past leg stump when he played back to Dockrell, was by a distance the least convincing of Rogers' innings. But the enterprise he had shown was more than worthy of some good fortune, and it was also entirely fitting that the same run took Middlesex into the lead.

The 150 stand was raised in 237 balls, and Denly marked the occasion by hoisting Dockrell for six to wide long on. Rogers took further liberties with Suppiah's very slow left-arm spin, twice swinging him unmercifully into the Mound Stand. More arresting was a smear through cover off Trego, which was followed up with a heave well into the Tavern Stand after the bowler moved around the wicket. Somerset had no answer to Rogers in this sort of mood, and it is worth pausing to wonder how many bowlers would have.

Daniel Brettig is an assistant editor at ESPNcricinfo. He tweets here