PML-N's Shaista Pervaiz Malik won the NA-133 constituency, enabling her party to retain the seat that has long been the party's stronghold, unofficial, preliminary results showed.
Malik defeated PPP opponent Aslam Gill by a margin of 14,498 votes, according to the unofficial results, securing 46,811 votes, versus Gill's 32,313.
The PML-N has won the seat for the fourth time since 2008, although by a smaller margin this time around, as compared to when the party won it in the 2018 elections.
In 2018, Pervaiz Malik secured 89,699 votes, which means PML-N got 42,888 fewer votes this time.
PPP's Gill however got 26,728 more votes now as compared to the 2018 polls, when he obtained only 5,585.
PTI's Aijaz Chaudhry won 77,293 votes in the 2018 general elections.
Shaista Pervaiz Malik succeeded her late husband Malik Pervaiz whose death left the NA-133 seat vacant.
Celebrations broke out in the PML-N camp even as results for at least 10 polling stations were not in.
A statement was issued by the party on Twitter, quoting its president Shahbaz Sharif as congratulating all the workers.
"I also congratulate the winning candidate Shaista Pervaiz Malk," the statement quoted Shahbaz as saying.
"The PML-N has proved in every by-election that it is the most popular party (in the country)," Shahbaz said.
The PML-N president said that the people are "looking to PML-N" to solve all the deep crises that have befallen them.