CHRISTCHURCH, New Zealand, March 14 (Reuters) - Mohammad Sami, a virtual unknown a week ago, will be a marked man in the second test against New Zealand starting on Thursday.

Of all the big names to roll off Pakistan's prolific production line of pace bowlers in recent years, few have made as immediate an impact as the inexperienced 20-year-old.

After taking three wickets in the first innings of his test debut this week, he produced an extraordinary seven-over spell of high pace and later reverse swing on the final day which included five wickets for six runs.

Pakistan manager Fakir Aizasuddin said: ``No-one could have done better this morning. He was unplayable.''

Physically, Sami has been likened to former Pakistan pace bowler Aaqib Javed. His figures in Auckland, though, echoed past performances by the likes of Imran Khan, Wasim Akram, Waqar Younis and Shoaib Akhtar.

It was injuries to Akram and Akhtar, the ``Rawalpindi Express'' and vying for the tag of the world's fastest bowler with Australian Brett Lee, which led to the Karachi right-arm bowler's debut.

Sami, taught to reverse swing the ball by Akram and Waqar, had only played one domestic trophy before the New Zealand tour and was overlooked for the one-dayers preceding the test series.

His five for 64 in the final of this season's Quaid-e-Azam trophy against the Lahore Blues, however, turned heads this season, particularly those of Akram and fellow test player Abdur Razzaq as they trudged back to the pavilion.

Sami's opening burst in Christchurch will be awaited keenly.

He will start with a hat-trick ball after his last two deliveries of the first test clean bowled James Franklin and Daryl Tuffey.