India scored a thrilling five-run victory in the first One-day International on Saturday in this port city, where some 4,000 people have died in political and sectarian violence over the last five years.
But not a stone was hurled at the players by the capacity crowd of 33,000 in the National Stadium and "no anti-India slogans were chanted", police said after the dramatic resumption of cricketing ties between the South Asian rivals.
The fans proved to be "most sporting crowd," city police chief Asad Ashraf Malik said, after fears of terrorism were expressed ahead of the match at the start of India's first tour of Pakistan in 14 years.
"Karachiites have proved that they are peace-loving people and could have hosted a Test match as well."
India refused to play a Test in Karachi over security concerns, saying they did not want to stay for long in the city.
But Malik said: "The people's behaviour in such a hot and humid day was excellent and hats off to them."
Fans applauded both teams throughout the match, clapping every run and every wicket. Many spectators painted their faces with colours of their national flags, while some were even seen carrying the flags of both India and Pakistan.
However security was tough for the match both inside and outside the ground.
"We were on duty for three days. We came here at dawn on Saturday. Our job was to keep an eye on the fans," police constable Mohammad Ramzan said.
"I am happy and relaxed everything was perfect. I can now go back to my home and take some rest."
The provincial Government declared Saturday a holiday and most roads were deserted throughout the day. Private clubs and restaurants made special arrangements to show the match on huge screens.
"Cricket fans are mad about the game. They are not so stupid that they would attack the team and its players," a woman fan said.
"We consider them our guests whether they are Indians or Australians."
Shopkeeper Mohammad Usman said: "Peace and not merely cricket won in Karachi on Saturday.
"Yes, there have been some incidents of terrorism by a few militants, but the majority of people of this city are peaceful and it should not be potrayed as a 'city of followers of Al-Qaeda'."
Karachi was hit by two suicide car bombings in 2002, which killed several foreigners as well as Pakistanis. Eleven French engineers died in an attack outside the Sheraton hotel on May 8, 2002.
The New Zealand and South African cricket teams have refused to play matches in Karachi.
"You cannot judge the city because of a few bomb blasts and sectarian-related killings," said social worker Abdus Sattar Edhi.
"There is another side of the city as well and the way thousands of people cheered for Indians and Pakistan players could be an eye-opener for those who refused to play here."
He added: "The peace-loving people have welcomed the cricketers as well as politicians like Priyanka Gandhi."
Priyanka, daughter of slain Indian premier Rajiv Gandhi, watched the match and signed autographs for dozens of fans.