The International Cricket Council's Anti-Corruption Unit asked to see video tapes of the game as part of its ongoing crusade to prevent corruption in the game.
Sri Lanka won the match by eight wickets, and reports claimed the dismissal of Pakistan batsman Yousuf Youhana, in particular, was being scrutinised.
Youhana was run out for nought without facing a ball.
But the Agence France Presse quotes an ICC source as saying: "The matter is over and Pakistan does not have to worry about anything."
The Champions Trophy is being used as a trial run by the ICC security team ahead of next year's World Cup in South Africa.
They have confirmed that "detailed monitoring" of every game in the 12-nation tournament is being carried out.
Lord Condon, head of the ACU, said earlier this week: "No one should be surprised at this approach and the unit will be looking at other incidents in other matches during the course of the remaining 10 games of the tournament."
"The ACU is confident that this regime is providing an effective and professional deterrent that will protect both the integrity of the tournament and the privacy of the players."
The ACU was formed two years ago after the match-fixing scandal which led to life bans on three Test captains - the late Hansie Cronje of South Africa, Mohammad Azharuddin of India and Salim Malik of Pakistan.