The win lifted the hosts to 10th in League One and it also meant a first defeat for new Brentford boss Nicky Forster in his seventh game in charge. And he could have few complaints as his side was second best by some distance.
Monkhouse opened the scoring after 36 minutes when his shot crashed off the underside of the crossbar and bounced over the line, with assistant referee Simon Clayton flagging to confirm it had gone in.
Pools’ Antony Sweeney headed past his own post in a rare defensive scare, but Monkhouse grabbed his fifth goal in six games shortly afterwards. Sweeney ran across the back four and laid the ball off for Monkhouse to drill home.
Brentford’s only real chance came when Gary Alexander turned inside the six-yard box and Scott Flinders saved with his legs.
And Pools finished the game off in the 84th minute. Colin Larkin’s deep cross was nodded back across goal by Leon McSweeney for Liddle to drill home from 12 yards.