Opening batsman Imam-ul-Haq hit a century and legspinner Shadab Khan grabbed a career-best 4/32 as Pakistan crushed Zimbabwe by 201 runs for their fifth biggest one-day international victory on Friday.
Left-handed Imam, the nephew of former Pakistan captain Inzamam-ul-Haq, made 128 off 134 balls in an imposing total of 308/7 after Zimbabwe captain Hamilton Masakadza won the toss and elected to field.
It was Imam's second career ODI century in his fifth match, and included 11 boundaries.
The Zimbabwe top-order batsmen struggled against Pakistan pace before Shadab ran through the tail as Zimbabwe was bowled out for 107 with 15 overs to spare.
Wicketkeeper-batsman Ryan Murray top-scored on debut with an unbeaten 32. No other Zimbabwe batsmen could cope with the pace or Shadab.
"If the team performs well, the captain is definitely happy," Pakistan captain Sarfraz Ahmed said. "We could have got more runs in the end but there was overcast conditions."
Imam and Fakhar Zaman, the star of the Twenty20 tri-series at Harare last week, saw off the Zimbabwe seamers by combining in a 113-run opening wicket stand to the 25th over.
Zaman made 60 off 70 balls with seven fours before he drove hard at new offspinner Liam Roche, who took a fine return catch.
Imam got a reprieve on 77 when Murray dropped a hard chance behind the wicket. He reached his century off 109 balls with a pulled boundary off Donald Tiripano (2-66).
Pakistan accelerated thanks to newcomer Asif Ali's 46 off 25 balls which included two sixes and four boundaries, while Imam reached his second fifty off only 34 balls.
Imam finally holed out in the deep in the 46th over, while Asif was also caught at long off while looking for his half-century with a big shot.
"I thought the seamers bowled well upfront and at the death, we lost it in the middle," Masakadza said. "We had too many soft dismissals ... and you can't chase 300 with that."
Left-arm fast bowler Usman Khan (2/21) got two wickets in his first two overs while seamer Faheem Ashraf also took two early wickets as Zimbabwe slipped to 55/5 in the 15th over.
Shadab baffled Zimbabwe's lower order as the home team was bundled out in 35 overs.
The remaining four matches of the series will also be at Bulawayo with the next match on Monday.