The fiery exchanges between Shane Watson and Mohd Aamer are good for the game, according to fast bowler Doug Bollinger.

The pair were involved in some entertaining by-play during the final session on day three of the Boxing Day Test at the MCG with the standout incident coming when Aamer rocketed a bouncer into Watson's shoulder in the 12th over.

Australia opening batsman Watson failed to get out of its path in time and ended up on the ground, prompting the emerging Pakistan paceman Aamer to mockingly blow Watson a kiss and clap his hands in front of the opener.

"It's good for the crowds, it's good for the game," said Australia left-armer Bollinger after the day's play.

"We don't want anything like what happened to come out again," he said in reference to the heated clashes with West Indies that led to four Australians, himself included, fined or reprimanded. "But it's good for a bit of fire and flair to come out.

"He (Aamer) bowls fast and fast bowlers are meant to be angry and have a bit to say and Watto batted well and stepped up. I think it's the old opening bowler-opening batter situation.

"You know, you have a new ball in your hand and you get a bit of fire and you have no-one else to blow up at so you blow up at the batsman."

Watson scored Australia's 21st half-century of the summer in the final session and remained unbeaten on 64 alongside Michael Clarke (21) as the hosts reached 111 for three - a lead of 307 - at stumps.

Australia are still in search of their first ton for the season after a raft of near-misses, three of which have been produced by Watson who scored 96 and 89 against the Windies before being run out for 93 on Boxing Day after a comical mix-up with Simon Katich.

However, Bollinger believes the prospect of a maiden Test ton will sit easy with Watson overnight.

"He'll sleep pretty sound. Some of the boys are tired - we've been working hard - but I think he'll be all right," Bollinger said of Watson, who has now scored seven fifties in 12 innings this year.

"He looks really sharp there and I think he really wants a hundred like most of us."

Bollinger ended with figures of three for 50 and was pleased with the pivotal role he played in dismissing Pakistan at tea for 258 in response to Australia's first-innings score of 454 for five declared. He snared three wickets in four overs with the second new ball.

Skipper Ricky Ponting took the second new ball as soon as it became available and Bollinger re-entered the attack with immediate results as he dismissed nightwatchman Aamer (15), Kamran Akmal (12) and Abdur Rauf (three).

"It was pretty hard work but I am really happy the way all of us stuck together and bowled them out," Bollinger said.

"I didn't think I was going to get a wicket there but I was happy to get three and come in confident. Hopefully we can knock them over in the following days."

And Bollinger is confident the wicket will help Australia do just that.

"The new ball's harder and it comes on a lot more but I think it's going to get lower on the following days and that will be beneficial for us as it will be harder to score," he said.

"You just have to keep it simple, just bash away as hard as you can, I don't know, try and get the ball to swing as much as you can reverse.

"I think we have to try and hit good areas and make them play low and hopefully some will stay low and we'll get a couple of lbws or bowleds."

The performances of emerging Pakistan stars Umar Akmal and Aamer, meanwhile, were cause for tremendous excitement for the tourists' camp.

Akmal started off the day with a dashing, but brief, half-century and 17-year-old Aamer ended it by sending Ponting and Michael Hussey back to the pavilion.

Akmal - who used the fence to score 42 of his 51 runs - added another seven boundaries and a six to his overnight total with four of those rope breaches coming in as many balls during an expensive Peter Siddle over.

The knock was the 19-year-old's fourth half-century in just his fourth Test match to go with the ton he scored on debut in New Zealand last month.

Two sessions later, paceman Aamer took centre stage to be Pakistan's most effective bowler in the hosts' second innings as he claimed two for 43 with a mixture of raw speed and aggression.

The efforts provided a rich source of encouragement for veteran Misbah-ul-Haq who top-scored for Pakistan with an unbeaten 65.

"He (Akmal) is an exciting player and he just wants to dominate any bowling," Misbah said.

"Especially it's really good to see him dominating the Australian attack and I think he has a big future ahead.

"He loves to play under pressure and he loves the challenges, I think that's really good for Pakistan.

"I think he (Aamer) is a really (exciting) prospect for Pakistan, a guy who is bowling 150km (an hour) is always an asset for the team.

"He's batting well and so he is a good asset for Pakistan."

But Misbah conceded his team's use of the referral system must improve after Aamer and Abdur Rauf practically threw away two unsuccessful challenges when they each contested a turned-down lbw appeal which was clearly not out.

When asked who was in charge of the referrals, Misbah replied with a chuckle: "I think the bowler, the wicketkeeper and the captain. Unfortunately it's not working well for us."