|Specsavers County Championship Division One, Trent Bridge, day three|
|Nottinghamshire 241 & 240: Mullaney 64; Rayner 4-83, Finn 3-57|
|Middlesex 247 & 48-3: Compton 26*; Ball 3-20|
|Middlesex (4 pts) need 187 more runs to beat Notts (4 pts)|
Nottinghamshire's Jake Ball took three wickets to dent Middlesex's County Championship title challenge as the leaders struggled in pursuit of 235.
Middlesex, who began four points clear of Yorkshire at the top of Division One, were 48-3 at the end of day three.
Ball, who took a hat-trick in the first over of the first innings, removed Nick Gubbins - with the first ball of the second - Sam Robson and Dawid Malan.
Notts posted 240 in their second innings as Steven Mullaney made 64.
Middlesex are in danger of being overtaken at the summit by Yorkshire, who are in control of their match against Durham at Headingley, while Somerset moved into title contention with victory over Warwickshire.
Bottom club Notts must win to retain any realistic chance of staying in the top flight.
Lower-order runs from Brett Hutton (32 not out) and Imran Tahir (16) left Middlesex with a tricky run chase, after Steven Finn (3-57) ripped through the hosts' middle order and Ollie Rayner (4-83) helped to polish off the tail.
Ball was in superb form once more with the new ball, forcing Gubbins to edge behind and bowling Robson before trapping Malan lbw in another inspired opening spell.
The England pace bowler ended day three with figures of 3-20 from seven overs, with Middlesex requiring a further 187 runs for victory on the final day.