In Karachi, Peshawar's Kamran Akmal hit a century against title-holder Quetta Gladiators.
Akmal smashed 101 runs off 55 balls and guided 2017 champion Peshawar to 153-4 in 18.3 overs in reply to Quetta's below-par effort of 148-5 at Karachi.
In Lahore, two-time champion Islamabad's heavily loaded overseas top-order rolled over Multan Sultan by eight wickets as it raced to 165-2 in only 16.4 overs.
Luke Ronchi hammered 74 off 45 balls and his Kiwi countryman Colin Munro smashed 50 off 32 in what proved to be an easy run chase after seamer Amad Butt's 4-27 had restricted Multan to 164-8.
Akmal gave the credit to Peshawar bowlers.
"My innings benefited my team and that matters to me a lot," Akmal said. "The real credit (for the win) goes to the bowlers, the way they bowled and restricted the opponents."
Akmal hit 13 fours and four sixes to record his third century in the PSL after previously scoring hundreds in the United Arab Emirates against Karachi and Lahore Qalandars in 2017 and 2018, respectively.
Earlier Quetta, which had defeated Islamabad in the opening game, struggled for runs against a four-man Peshawar pace attack after captain Darren Sammy won the toss and opted to field.
Opening batsman Jason Roy of England top scored with an unbeaten 73 off 57 balls as Wahab Riaz (2-21) and Mohammad Amir (1-24) never allowed the batsmen to score freely and Quetta was restricted to under the 150 mark.
Hasan Ali looked rusty in the first match when he gave away 52 runs in his comeback match from back injury. He couldn't get a wicket Saturday but pinned down the batsmen in the latter half of the innings and gave away only 22 runs in his four overs.
Quetta couldn't recover from Akmal's early onslaught. Pakistan's former wicketkeeper-batsman smashed leftarm spinner Mohammad Nawaz for two sixes and two fours in a 21-run first over of the innings and then hit fast bowler Sohail Khan for two fours and a six in the second over.
Nawaz had an off day in the field when he dropped Akmal on 94 at point before the batsman completed his century off a top-edged sweep against legspinner Fawad Ahmed and ran for two.
Akmal was dismissed off the next delivery when he holed out in the deep before Liam Livingstone finished off the match with a straight six off Ahmed.
In its opening game, Peshawar lost to Karachi Kings.
For Islamabad, the New Zealand pair of Ronchi and Munro smashed 63 runs in the first six overs and set an early tone to the chase by hitting legspinner Imran Tahir for 22 in the second over. The South African finished with 0-44.
Munro clubbed four sixes and three fours before he was clean bowled by veteran Shahid Afridi after a match-winning opening stand of 92 runs off 59 balls.
Ronchi hit nine fours and two sixes in his half century and was reprieved on 69 when Multan captain Shan Masood dropped an easy catch at mid-off. Ronchi departed with only two runs required for victory as James Vince timed his jump to perfection to hold onto a catch over his head off a mistimed pull shot against seamer Mohammad Ilyas.
Earlier, Multan's Zeeshan Ashraf hit 50 off 29 and Vince made 42 off 31, but Amad had Moeen Ali (10) and Rilee Rossouw (0) in his second over to restrict the opposition.