It took a full bruising half hour for the game to settle down and for both sides' passing games to flourish. As a consequence there was a flood of goalmouth action at both ends before the interval.
Both teams were guilty of wasteful final passes, but Accies, without creating any real chances, were encouraged by some unusually nervy goalkeeping from Killie's Alan Combe, who struggled under several first-half crosses.
As the half progressed, Kilmarnock looked the likelier to score and Australian Danny Invincibile wasted a good chance when he blazed over the top after good work on the right wing from James Fowler.
Hamilton keeper Tomas Cerny had to pull off a brilliant reflex save in injury time to deny Conor Sammon his first SPL goal from a flicked near-post header from a Mehdi Taouil corner kick.
Killie changed their tactic for the resulting corner and the Moroccan swung the ball in deep and Pascali rose highest to head home from four yards to ensure a half-time advantage.
Garry Hay thought he had doubled his team's lead when he volleyed acrobatically past Cerny only to see the offside flag raised.
Kilmarnock continued to keep Accies at arm's length and could have gone two up in the 67th minute. Sammon did well to flick the ball into the path of the breaking Craig Bryson and he ran away from the defence, but prodded the ball wide from the edge of the box.
Hamilton weren't giving up the league's top spot lightly and produced their most fluent move of the match in the 75th minute down the right wing.
When the cross was delivered, Richard Offiong looked set to pounce, but Frazer Wright made a brilliant intercepting header to deny the big striker who had been a handful all afternoon.
Accies' task became even harder 12 minutes from time when David Graham was shown a red card for a frustrated lunge at matchwinner Pascali.
Cerny produced another great save, this time with his feet, when a wayward cutback ran kindly for Invincibile five minutes from time.