Already the scorer of the fastest first-class hundred this season, off 72 balls against Kent, Warne was in touching distance of a ton as he warmed the shivering crowd at the Walker Ground.
He reached his fifty with a straight six lofted over the head of the left-arm spinner Chris Peploe and punched his bat in delight before turning towards the Hampshire players gathered in the marquee to acknowledge their appreciation of his effort.
Warne had gone into tea having scored 18 at a run a ball. When he re-emerged refreshed, he clubbed the first over after the interval, bowled by Scott Styris, for 17 and hit a couple more boundaries in the New Zealander's next over.
The six that brought him the half-century came in the same Peploe over that saw Dimitri Mascarenhas also thump a six. However, when their eighth-wicket stand had reached a hundred, Styris ended the partnership.
Warne refused to let up, though, and was clearly determined to show that what was also his maiden hundred at Canterbury in May was no fluke. He might have been a trifle more cautious as the Middlesex captain, Ben Hutton, juggled his bowlers in an effort to break through the Australian's defences, although he did wallop Melvyn Betts for another six.
Earlier, it needed some studious batting from John Crawley to stave off disaster after Hampshire had slipped to 61 for 4 as the Middlesex swing bowlers exploited the heavy atmosphere.
Crawley's innings did more than rescue his team, it also spared Warne's blushes since he had decided to bat. Crawley compiled his second half-century in successive Championship innings and shared in a stand of 69 with Nic Pothas.
There was also a punchy 33 off 41 balls from Sean Ervine, an innings which indicated that conditions were now favouring the bat. So it proved when Warne arrived at the fall of the Zimbabwean's wicket.