New Zealand paceman Iain O'Brien celebrated his 33rd birthday by taking a second successive six-wicket haul for Leicestershire as the batsmen struggled on the first day of the LV County Championship game against Middlesex at Grace Road.

Middlesex were bowled out for 159 with O'Brien claiming six for 39 to follow up his return of six for 87 against Derbyshire last week.

But Leicestershire then slumped to 53 for five in their reply before Josh Cobb spearheaded a recovery with an unbeaten 65 and the home side closed 22 runs behind at 137 for six.

Fast bowler Steve Finn claimed four of the wickets for 54 runs.

Although Middlesex had no hesitation in deciding to bat there was enough in the pitch to encourage the bowlers with some variable bounce the major concern for the batsmen.

O'Brien bowled superbly in an opening spell that brought him two wickets for 19 runs in eight overs - and 12 of them came in one over when he was hit for three boundaries by Owais Shah.

O'Brien's first victim was Nick Compton who was trapped lbw by a perfect yorker and the New Zealander then gained revenge on Shah by knocking back his off stump with another fine delivery.

And when O'Brien was brought back for a second spell just before lunch he quickly claimed another scalp having Eoin Morgan caught at slip, leaving Middlesex in real trouble at 75 for four.

Only Dawid Malan offered any real resistance by scoring a spirited half-century off 74 balls.

But O'Brien was not to be denied and picked up two more wickets in his fourth over of the afternoon, trapping Gareth Berg lbw with a ball that skidded through and then uprooting Shaun Udal's middle stump before surprisingly being taken out of the attack.

Harry Gurney nipped in for the wickets of Murali Kartik and Tim Murtagh before O'Brien returned to have Finn lbw, leaving Malan unbeaten on 67 off 74 balls with nine boundaries.

But Leicestershire found batting just as uncomfortable and Finn ripped through their top order in a lively 10 over spell that brought him four of the first five wickets.

Only Cobb of the top six managed to reach double figures as he continued the excellent form he showed when he made a double century for England under-19s against Bangladesh.

He was finally given support by Tom New with the two of them sharing a sixth-wicket stand of 73 in 28 overs.

Cobb reached his fifty off 74 balls, with seven fours and two sixes, but New was dismissed shortly before the close for 42 caught of bat and pad off the bowling of Udal.

New's dismissal meant 16 wickets had fallen in the day for a total of 296 runs.