Pakistan will start their first Test series at home against Australia in 24 years in Rawalpindi on Friday under heavy security.

As the long-awaited and potentially fascinating three-Test battle series unfolds, here is a list of six players — three from each side — who could hold the key to their respective team's success.

Australia

Steve Smith

Started his career as a leg-spinning all-rounder against Pakistan at Lord's in 2010 before developing into one of the most complete batters in international cricket.

His average of 59.87 is unsurpassed by any active Test player and he has proved his adaptability by scoring 1,200 runs in 13 Tests on slow, turning sub-Continent wickets.

Australia will look to Smith -- who by his own lofty standards had a lean series against England with 244 runs at 30.50 and a top score of 93 -- to anchor their batting against a formidable Pakistan attack on pitches alien to the tourists.

Nathan Lyon

Likely to be the key to winning matches on the slow and turning pitches of Pakistan.

With 415 Test victims, Lyon is Australia's greatest off-spinner and as a slow bowler his tally for his country is only bettered by leg-spinner Shane Warne, who took 708 wickets.

Lyon, who has taken 95 wickets in 19 Tests in Asia, has a knack of understanding how pitches behave and subtly change over the course of a five-day match, having worked as a curator in his early days of the career.

Marnus Labuschagne

The world's top-ranked batsman shot to prominence when he replaced Steve Smith as concussion substitute in the 2019 Ashes Test at Lord's and scored fifty.

His 23 Tests have seen him score 2,220 runs at 56.92 with six hundreds.

Labuschagne's maverick batting style puts him firmly in the same mould as teammate Smith who is the only active player in Tests with a higher average.

His eccentricity and meticulous approach meant he spent the few weeks practising at his house on a home-made mat with aluminium strips taped to it, to try to replicate conditions he may face against Pakistan's spinners.

Pakistan

Shaheen Shah Afridi

Since making his Test debut as an 18-year-old three years ago, the tall left-armer's rise has been remarkable.

He possesses a wicked inswinger to right-handers that blew arch-rivals India away in the Twenty20 World Cup last year.

Shaheen's red-ball record stands up to scrutiny too -- he was the second highest wicket-taker in Tests last year with 47, just behind Ravi Ashwin's 54 for India.

His 78 wickets in all international cricket in 2021 saw him win the ICC Player of the Year award.

Fawad Alam

While names such as Babar Azam and Mohammad Rizwan hog the headlines, Fawad Alam pretty much flies under the radar when the vice versa should be the case — at least in the longest format.

Over the last 12 months, no Pakistan batsman has a better average in Tests than Fawad's 76.60. To put this into context, Babar (36.75) and Rizwan's (36.33) combined average is also less than Fawad's gargantuan number.

An extremely unorthodox middle-order grinder, Fawad can survive for long hours and provides the team a stubborn spine against dangerous bowling attacks.

Sajid Khan

With an unusual action, Sajid has taken over the off-spinning duties from Bilal Asif who was Pakistan's match-winner against Australia in the 2018 series win in the UAE.

Sajid appears to bowl off the wrong foot, which can be disconcerting for batsmen as he proved by taking 12 wickets against Bangladesh in Pakistan's last Test outing in December.

Like all off-spinners, loves to operate out of the bowlers' rough outside the left-handers' off-stump, which could pose problems to Australia's lefty quartet of David Warner, Travis Head, Usman Khawaja and Alex Carey.