PSG fired a significant warning of intent throughout Europe with a 4-0 rout of Barca in the French capital three weeks ago and will aim to complete the job in the return leg at the Camp Nou on Wednesday.
But the Catalan giants go into the game buoyed by thumping 6-1 and 5-0 wins in their past two league matches and haven't given up hope of staging an unprecedented comeback.
No side has lost 4-0 away from home in Europe and gone through in a two-legged tie, but with Barca's prolific front three of Neymar, Lionel Messi and Luis Suarez they cannot be entirely discounted.
"It's really important that our spirit is on the way up and our confidence too. I see us on the up and with confidence. On Wednesday we are going to play really well."
More From This Section
Barca knocked PSG out at the quarter-final stage in both 2012-13 and 2014-15, but the reigning French champions have the upper hand this time and January signing Julian Draxler is confident of reaching the last eight for the fifth year in succession.
"Many teams have lost 5-0 at the Camp Nou, we know that anything is possible," Draxler told PSG's club website. "But deep down I'm convinced we'll qualify for the quarter-finals.
Bayern Munich have one foot in the next round after thrashing Arsenal 5-1 at the Allianz Arena and look set to eliminate the Gunners in the last 16 for the third time in the past five seasons.
- 'Full throttle' -
===================
"We have a big advantage, but Arsenal are dangerous, so we have to go full throttle to win," said Spain international Javi Martinez, who netted his first goal of the season in Saturday's 3-0 victory at Cologne.
Philipp Lahm will miss the game through suspension, but the Bayern skipper said his team-mates would aim to extinguish any lingering hopes Arsene Wenger's men have right from kick-off in London.
Holders Real Madrid head to Napoli as clear favourites after a 3-1 win in the Spanish capital, but such an advantage has not always proved a guarantee of success for the record 11-time champions.
Real have held a similar lead on eight previous occasions in European competition but only progressed half of the time, providing Napoli with reason to dream they can pull off a shock.
Borussia Dortmund trail 1-0 ahead of the visit of Benfica to Signal Iduna Park on Wednesday.
Pierre-Emerick Aubameyang missed a penalty as Kostas Mitroglou's second-half strike in Lisbon last month gave the Portuguese outfit the edge in their tie.
But the Gabonese striker netted his 20th and 21st goals of the Bundesliga season in Saturday's 6-2 drubbing of Bayer Leverkusen to move back in front of Bayern marksman Robert Lewandowski at the top of the scoring charts.