With the series locked 2-2, the day-night encounter at the Gaddafi stadium is all to play for and will give the winner the psychological edge ahead of the three Tests to follow.
Sourav Ganguly's Indians go into the showdown buoyant after securing the series-levelling win on Sunday, but are wary of their poor record in One-day finals over the past year.
Pakistan, on the other hand, are concerned about their undisciplined bowling performance so far that allowed India to bounce back when a decisive 3-1 lead for the hosts was on the cards.
Ganguly's tourists have previously come unstuck when it mattered most, losing four consecutive finals to world champions Australia, starting with the 125-run defeat in the World Cup final in South Africa in March last year.
The Indians were then beaten on their home turf in Kolkata in November in the tri-series final and were blanked 2-0 in the best-of-three finals in Australia in February.
"We have not played well in crunch finals," Indian vice-captain Rahul Dravid conceded. "That is something we definitely want to improve upon on Wednesday. But our morale is high after Sunday's win and this should help us in the next game."
The tourists kept their cool in the make-or-break fourth game in Lahore to overtake Pakistan's seemingly unbeatable 293 for nine with five overs to spare.
Dravid himself led the way with an unbeaten 76, adding a match-winning 132 for the sixth wicket with Mohammad Kaif, who returned unconquered on 71.
India have been helped along in the series by the wayward Pakistan bowlers, who have conceded a staggering 58 wides and 40 no-balls in the four matches so far.
Fiery fast bowler Shoaib Akhtar was the worst culprit on Sunday, giving away 14 wides in his 2-63 in nine overs. New-ball partner Shabbir Ahmed conceded five no-balls and a wide in 0-62 from seven overs.
Pakistan captain Inzamam-ul-Haq, who has twice ended up losing despite scoring centuries in the first match at Karachi and on Sunday, was exasperated.
"I would he happy to be out for a duck if Pakistan win the last game," he said.
"The advantage we held after taking a 2-1 lead at Peshawar is gone. India now have the upper hand. After Sunday's win, they will not only have the momentum with them, but also the confidence that comes from successfully chasing a big score like 293.
"As a captain, a no-ball or a wide irritates me no end. The lack of discipline by the bowlers cost us the match. It is about time they put their hands up and do the job for Pakistan."
The playing elevens for the decider described by former Indian Test player Navjot Sidhu as "too close to call" will be named just before the toss on Wednesday.
India is expected to retain the same side, while Pakistan is seeking a place for dashing opener Taufiq Umer, who hit a century in a practice match against the Indians on March 10.
India (likely): Sourav Ganguly (capt), Rahul Dravid, Virender Sehwag, Sachin Tendulkar, Venkatsai Laxman, Yuvraj Singh, Mohammad Kaif, Zaheer Khan, Laxmipathy Balaji, Irfan Pathan, Murali Kartik.
Pakistan (from): Inzamam-ul-Haq (capt), Yousuf Youhana, Shahid Afridi, Yasir Hameed, Younis Khan, Shoaib Malik, Abdul Razzaq, Moin Khan, Shoaib Akhtar, Mohammad Sami, Shabbir Ahmed, Taufiq Umer.