All three Asian giants are missing frontline bowlers but still look the only contenders to win the six-nation event, which also features Bangladesh and qualifiers United Arab Emirates and Hong Kong.
Sri Lanka, winners of the title three times, are without Lasith Malinga who has been injured since March, and Farveez Maharoof who suffered a side strain on the eve of team's departure for Pakistan.
Four-times champions India are badly depleted in their bowling attack with Zaheer Khan and Shanthakumaran Sreesanth injured, and off-spinner Harbhajan Singh serving a five-match ban on discipline charges.
A groin injury has also ruled out their star batsman Sachin Tendulkar.
Pakistan miss Mohammad Asif who returned home after a 19-day detention in Dubai on charges of possessing illegal drug and faces an internal inquiry.
His pace partner Shoaib Akhtar is serving an 18-month ban over discipline violations.
Pakistan captain Shoaib Malik said it looked a three horse race.
"Asia Cup traditionally pits India, Sri Lanka and Pakistan in a three-way battle and although conditions in these countries are the same, we have slight home advantage," said Malik, whose team beat India to lift a tri-series in Bangladesh on June 14.
The win, Malik feels, gave Pakistan a confidence boost.
"We are high on spirits after the tri-series win in Bangladesh but we have to play well to cash on to that," said Malik, whose country is hosting the event for the first time since its inception in 1984.
Pakistan have won the Cup once, also in Bangladesh in 2000.
The hosts take on Hong Kong here in a Group B match on Tuesday. India is the third team in the Group. On the same day Bangladesh meet UAE in Lahore in Group A, which also has Sri Lanka.
The top two teams from each group will qualify for the super league where each side will play each other to decide the July 6 finalists.
Sri Lankan skipper Mahela Jayawardene said he hoped his team could overcome a slump in form which has seen them lose four of five one-day series since finishing runners-up to Australia in the World Cup last year.
"We have not been in the best of forms in the last few months, but this is another opportunity to show what we are capable of. The fact that we are defending champions makes this competition even more special," said Jayawardene.
The islanders brought their dashing left-handed batsman Sanath Jayasuriya back after leaving him out of the West Indies tour earlier this year.
Turning 39 next week, Jayasuriya will supplement Sri Lanka batting which lacked aggression in recent matches.
In Muttiah Muralitharan and puzzling Ajantha Mendis, Sri Lanka have two quality spinners -- a fact Malik admires.
"Sri Lanka have two very good spinners who can be useful on our pitches," said Pakistan captain.
India have recently done well, beating world champions Australia in a tri-series in February. They crushed Pakistan by a record 140 runs in the tri-series in Bangladesh but looked overconfident before losing the final.
Bangladesh face a tough task of beating giants to harbour any hopes of reaching the final. They are without their two top players in Aftab Ahmed (finger injury) and Shakib Al Hasan who opted out due to exams.
The UAE and Hong Kong hope to gain experience by competing against the stronger opponents.
The two minnows qualified for the Asia Cup after UAE beat Hong Kong in the final of the ACC (Asian Cricket Council) Trophy in 2006.