Defending champions Lancashire fell to the foot of the LV= County Championship first division table despite rain almost completely washing out a full list of fixtures on Wednesday.
Only Lancashire's fellow relegation rivals Worcestershire were able to host any play as seven of the eight games failed to resume on a miserable day across the country.
The Pears had to wait until 4.30pm to start but their patience was at least rewarded with the batting points to edge them off the bottom.
Starting at 295 for eight Worcestershire soon passed 300 - and an extra bonus-point - before Toby Roland-Jones (five for 72) completed his five-wicket haul to bowl the hosts out for 323.
Opener Daryl Mitchell remained to carry his bat through the innings with an unbeaten 133.
Middlesex were 49 for none, with Chris Rogers 17 and Sam Robson 27, before the rain returned at 6pm.
Lancashire, 18 points adrift of safety, saw their survival hopes undermined further as rain left them marooned on 221 for six against in-form Durham at Liverpool.
Surrey are closest to the bottom two and their match at Somerset is poised with th hosts 42 for two after Kevin Pietersen's 163 inspired his side to a first-innings 317.
Leaders Warwickshire missed the chance to put more ground between themselves and second-placed Sussex, who are not in action this week, as they remained on 298 for five against Nottinghamshire at Edgbaston.
There was no play at all in the second division to offer some respite for leaders Derbyshire after they slipped to 28 for three in response to Essex's 245 on Tuesday.