Celtic produced a blistering second-half display to blow away Kilmarnock's brave hopes at Rugby Park and regain their daunting 13-point lead at the top of the Premier League.

The champions were almost punished in the first half after Henrik Larsson had squandered two glorious chances when youngster Kris Boyd missed an even better chance on the stroke of half-time.

Kilmarnock's youngsters had enhanced their reputations, but Martin O'Neill's side proved experience counts after the break with a rejuvenated display to kill off the Killie kids.

John Hartson fired home from the penalty spot for his 11th SPL goal after assuming control from regular penalty-taker Larsson before Paul Lambert wrapped it up with a clinical strike.

Celtic should have made the dream start after a glorious opportunity came their way after just one minute.

Lambert dummied Jackie McNamara's in-field pass and was threaded through by Neil Lennon, but after picking out Larsson in the centre, the striker flicked the ball wide with just Gordon Marshall to beat.

Kilmarnock looked dangerous on the break, but it was the visitors who threatened to open the scoring early on.

Alan Thompson curled a left-foot free-kick around the home side's wall from 25 yards in the eighth minute, but Marshall read the effort and comfortably saved by his right post.

The former Celtic goalkeeper was looking to get one over his former side and a minute later he did well to save Hartson's powerful right-foot shot from McNamara's pass.

The Hoops defence came under siege in the 22nd minute after Bobo Balde gave away a needless free-kick just outside the box for clumsily clattering into Boyd from behind.

The wall blocked Calderon's shot and Balde deflected Paul di Giacomo's header wide from Stephen Murray's cross before Alan Mahoon lashed a right-foot shot wide of Robert Douglas' post.

Larsson again had a great chance to give the visitors the lead in the 27th minute.

The Swede was sent away by Thompson and held off the challenge of Frederic Dindeleux, but again with just Marshall to beat he pulled his right-foot effort wide of the post.

Celtic, however, almost paid for that four minutes later when Stilian Petrov flicked Murray's corner towards the back of his own net, but McNamara saved him with a header off the line.

The pint-sized Kilmarnock winger, who was voted young player of the month, was causing Celtic all kinds of problems, but di Giacomo could not capitalise on his pass moments later.

The game threatened to boil over in the 36th minute as Thompson was booked for a foul on Peter Canero which sparked an angry reaction from the highly-charged Kilmarnock support.

Douglas then kept the scores level two minutes before the break with a spectacular one-handed tip over the crossbar from Kevin McGowne's long-range effort.

Just like Larsson before him Boyd spurned a great chance to give Kilmarnock the lead on the stroke of half-time.

He was picked out in the centre by the impressive Murray, but he headed wide from just five yards out.

Kilmarnock had to weather an early second-half storm as Celtic came out at the break with all guns blazing.

The visitors were awarded a free-kick in the 48th minute after McGowne fouled Larsson, but Marshall got down well by his left-hand post to save Thompson's long-range strike.

Celtic, however, were awarded a penalty in the 51st minute after referee John Underhill adjudged Canero to have fouled Petrov in the box after exchanging passes with Larsson.

Hartson took the ball from Larsson after missing some spot-kicks recently and his lack of conviction in front of goal tonight.

The Welshman stepped up and emphatically found the bottom corner beyond Marshall's hands to give the visitors the lead.

Kilmarnock came roaring back and Douglas needed to save low to his right to deny Calderon's effort from long range.

Manager Bobby Williamson granted former Celtic star Tommy Johnson his wish to come on against his former club for Boyd in the 57th minute, but it was to be frustrating for him.

As they committed more men forward they were leaving themselves exposed at the back.

Larsson though was having an off-day and miscontrolled McNamara's pass and the ball ran through to Marshall.

Lambert, however, made no mistake in extending Celtic's lead on the hour after Dindeleux failed to clear the danger and the midfielder blasted his right-foot shot home past Marshall.

Hartson went agonisingly close to killing off the home side in the 64th minute when his glancing header from Thompson's corner came back off the crossbar.

Kilmarnock were clearly rattled and Johnson fired well wide after being played into space by Calderon.

The performance of the Kilmarnock youngsters against Celtic gave them hope for the future - but Celtic's un unstoppable stars are refusing to give closest title challengers Rangers a look in.

Teams

Kilmarnock: Marshall, Canero, McGowne, Dindeleux, Hay, Mitchell, Mahood, Calderon (Jaconelli 85), Boyd (Johnson 58), Di Giacomo, Murray (Fowler 80).

Subs Not Used: Meldrum, Sanjuan.

Booked: Hay, Canero, Murray.

Celtic: Douglas, Balde, Valgaeren, Mjallby, McNamara, Petrov, Lennon (Petta 76), Lambert, Thompson, Larsson, Hartson.

Subs Not Used: Gould, Moravcik, Maloney, Smith.

Booked: Thompson, Hartson.

Goals: Hartson 51 pen, Lambert 61.

Att: 11,689

Ref: J Underhill (Scotland).