Match ends, Cambridge United 2, Portsmouth 6.
Matt Tubbs scored a hat-trick as Portsmouth thumped Cambridge to claim just a second away win of the season.
Jed Wallace fired Pompey ahead before debutant Nathaniel Mendez-Laing equalised with an angled finish.
Tubbs powered in and scored a header either side of Paul Robinson's goal as the visitors led 4-1 at the break.
Robbie Simpson reduced the deficit with a flying header but Ryan Taylor prodded home from close range and Tubbs tapped in Taylor's cross to complete the rout.
The win for Andy Awford's side extends their unbeaten league run to six games while Cambridge have now lost four out of their last five.
Portsmouth manager Andy Awford told BBC Radio Solent:
"We are really pleased with the three points; a real solid professional performance and I am delighted for everybody.
"It shows as a unit we have got good players in the team. When we click like we did today we are a very good side and it's not just the attacking players because the whole system worked and thankfully we have come away with three points.
"Today is about thanking the supporters for sticking with us and for us to come away to a difficult place like Cambridge.
"To score six goals is for those supporters who stick with us, not just this season, but over the past few seasons. You are not going to win six every week but I think they appreciate the effort by everybody and I certainly appreciate what they do for the football club."
- 17HughesSubstituted forMorrisseyat 81'minutes
- 9SlewSubstituted forKaikaiat 62'minutes
- 32BirdSubstituted forTaitat 45'minutes
- 3WhatmoughBooked at 47mins
- 21DunneSubstituted forAtanganaat 85'minutesBooked at 90mins
- 8J Wallace
- 29HollandsBooked at 9minsSubstituted forErtlat 77'minutes
- 9TaylorSubstituted forChaplinat 84'minutes
- Seb Stockbridge
- Shots on Target
Second Half ends, Cambridge United 2, Portsmouth 6.
Nigel Atangana (Portsmouth) is shown the yellow card.
Ryan Donaldson (Cambridge United) wins a free kick in the attacking half.
Foul by Nigel Atangana (Portsmouth).
Foul by Robbie Simpson (Cambridge United).
Nigel Atangana (Portsmouth) wins a free kick in the attacking half.
Corner, Cambridge United. Conceded by Jack Whatmough.
Robbie Simpson (Cambridge United) wins a free kick in the attacking half.
Foul by Jack Whatmough (Portsmouth).
Corner, Portsmouth. Conceded by Michael Nelson.
Substitution, Portsmouth. Nigel Atangana replaces James Dunne.
Substitution, Portsmouth. Conor Chaplin replaces Ryan Taylor.
Nathaniel Mendez-Laing (Cambridge United) wins a free kick on the right wing.
Foul by Johannes Ertl (Portsmouth).
Goal! Cambridge United 2, Portsmouth 6. Matt Tubbs (Portsmouth) right footed shot from very close range to the bottom right corner. Assisted by Ryan Taylor.
Corner, Portsmouth. Conceded by Ryan Donaldson.
Substitution, Cambridge United. Gearoid Morrissey replaces Liam Hughes.
Attempt blocked. Richard Tait (Cambridge United) left footed shot from the right side of the box is blocked.
Sullay Kaikai (Cambridge United) wins a free kick on the right wing.