* Azhar scores 12th test century
* Australia manage only two wickets (Adds quotes, details)
By Ian Ransom
MELBOURNE, Dec 27 (Reuters) - Opening batsman Azhar Ali shone in gloomy conditions with a patient, unbeaten century to guide Pakistan to 310 for six in the second test against Australia on Tuesday but both sides were left frustrated at the end of a rain-blighted second day.
Azhar was 139 not out with tail-ender Mohammad Amir on 28 as a rain-shower cut short another stop-start day at the Melbourne Cricket Ground.
After 39 overs were lost on the opening day, the weather wiped out the entire middle session, limiting Australia to two wickets while crimping Pakistan's hopes of forcing a result to keep the three-match series alive after the tourists lost the opener in Brisbane by 39 runs.
Rain aside, Azhar added to Australia's torment as he summoned all his powers of concentration to shrug off the delays and survive 287 balls.
He and Amir are likely to come out with all guns blazing in the morning to add quick runs and then send Australia in to bat.
"The decision has to be taken by the captain and coach in the morning how we have to play," paceman Wahab Riaz told reporters.
"But obviously we need to put some runs on the board so we can get some early wickets and put Australia under pressure."
Azhar and middle order batsman Asad Shafiq combined for a 115-run partnership and batted through the entire first session as Australia laboured with the old ball reaching the end of its life.
Resuming in the morning on 142-4, the pair added 90 runs to lunch before Australia broke through with the new ball after play finally resumed.
Shafiq tucked seamer Jackson Bird for a single to fine leg to bring up his 50 but was caught in the slips moments later, prodding uncertainly at a seaming delivery off the same bowler.
Captain Steve Smith, who grassed two chances in the first test win in Brisbane, took his third slips catch of the innings to make Shafiq Bird's third victim.
The breakthrough lifted the home side's bowlers, and Josh Hazlewood soon had wicketkeeper Sarfraz Ahmed caught in the slips for 10.
Tail-ender Amir came out swinging and was reprieved on one when he sliced a thick edge into the slips, only for Usman Khawaja to miss the flight of the ball which raced off harmlessly for four.
He beat the slips a number of times in a quickfire innings to add more misery to Smith's side.
Having taken over 90 balls to strike his first boundary on day one, Azhar opened his shoulders in the morning with a number of crisply struck boundaries.
A short break for rain left him stranded on 96, and Smith introduced himself and Nic Maddinson to bowl some part-time spin in an attempt to dislodge the opener before lunch.
On 99, though, Azhar glanced two runs down the leg-side off Maddinson to bring up the milestone, giving a little hop of joy before embracing Shafiq in celebration. (Editing by Amlan Chakraborty)