Pakistan must go back to their Champions Trophy triumph for inspiration and then look for early wickets in their World Cup encounter against arch-rivals India, suggests former captain Waqar Younis.

Bitter foes India and Pakistan lock horns in the tournament's one of the most anticipated matches at the Old Trafford on Sunday.

“It's simple - if Pakistan want to stay in the tournament, they have to bring an 'A-plus' performance and win that game,” Waqar said in his column for the ICC.

“When Pakistan play India it's always a huge game, but their meeting on Sunday is shaping up to be more crucial than ever.”

While he did not read much into India's all-win record against Pakistan in the World Cup, the pace great urged his country to look up to the title triumph in the 2017 Champions Trophy, where they beat India in the final.

“Pakistan have got to take positives out of what they did to India in the final of the ICC Champions Trophy a couple of years ago. They must think positively going into this game.I hope they have got their best game in the locker for India, who showed against Australia that they are a very fine side,” Waqar, one of the best fast bowlers of his time, said.

According to the former captain and coach, picking up early wickets could be key to Pakistan's chances.

“What I have seen in this World Cup so far is that if you don't pick up early wickets, you're in trouble. The new ball is so crucial and openers are being more careful in the first ten overs this year,” said Waqar.

“They're not really going full throttle, they are being a bit more watchful. Once you don't lose any wickets early on, it becomes easier because the ball doesn't swing and batting becomes easier.”