Association (PCA) Stadium sold out days ago for the crunch clash.
"We are not the most favourite team for this competition. India is the most favourite and we have played above expectations. We are very confident and we are enjoying our cricket," said Afridi.
But India captain Mahendra Singh Dhoni shrugged off the hype surrounding a match which has also taken on huge diplomatic and political significance.
"It's an honour to lead the side," said Dhoni. "If you take a pressure job, you will find yourself in a pressure cooker. When you talk about hype and pressure, what does not help you needs to be kept away.
"You need to top up on the skills aspect - vital areas we are focusing on."
The match will be a clash between Pakistan's well-balanced bowling attack and India's star-studded top order, including opener Sachin Tendulkar who needs just one more century for a hundred international hundreds.
"We believe we have the strongest bowling attack in the world," said Pakistan opening batsman Mohammad Hafeez, who took the new ball with his off-spin in the quarter-final win over the West Indies. "That's the key."
Pakistan's Umar Gul is arguably the best reverse-swing bowler at this tournament while Saaed Ajmal's off-spin a potent weapon.
And then there is the leg-spin of Pakistan captain Afridi who is the tournament's top bowler with 21 wickets at an average of just 10.71 apiece.
Meanwhile fast bowler Shoaib Akhtar, who will retire after the World Cup, waits in the wings.
Akhtar has played just three games at this tournament but the suspicion remains that India's batsmen can be troubled by high-class fast bowling.
"Shoaib is not 100 percent but I think he is trying his level-best and we will decide (on his selection) this evening," Afridi said.
India did manage to overcome champions Australia's three-pronged pace attack in a five-wicket quarter-final win in Ahmedabad but that was on a pitch favouring spin. Even then, India collapsed to 187 for five chasing 261 for victory, and it needed a composed 57 not out from the in-form Yuvraj Singh, now back on his home ground, to see the co-hosts to victory.
Traditionally, the Mohali pitch has always offered plenty of pace and bounce and that could yet see Pakistan give Akhtar one last shot at India.
Pakistan's ability to make early inroads into a top order featuring Tendulkar, Virender Sehwag and Gautam Gambhir could be decisive.
India's bowlers, notably left-arm quick Zaheer Khan and off-spinner Ravichandran Ashwin, did a good containing job against Australia.
India will look for similar results in a bid to book a place in the April 2 Mumbai final against either Sri Lanka or New Zealand.
This match has also witnessed "cricket diplomacy" with Pakistan Prime Minister Yousuf Raza Gilani accepting an invitation from India counterpart Manmohan Singh to attend the game.
"I think it's a great sign for both countries and sports, especially cricket always brings these two countries together," Afridi said.
Pakistan, who've yet to register an individual hundred at this event, have lost all four of their World Cup matches against India.
However, Hafeez said: "Pakistan has not defeated India in the World Cup but in the last 12 years, Australia also had not lost a single World Cup game. But then they lost to us (by four wickets) and to India.
"There is no point thinking about the past. We think about the day; whoever the opponent is, we try to win the day."