Following Wednesday's results, 16 sides have cemented spots in the Champions League knockout stage, and in doing so, relegated eight clubs to Europa League status.
With London giants Chelsea and Arsenal atop the bookmaker's picks for Europe's second-tier competition after topping their respective quartets, here's a look at the eight outfits the pair of Premier League rivals could face on the way to continental glory.
The only Belgian side to appear in two European finals, Jupiler League title holders Club Brugge drop down to the Europa League after finishing third in Group A, seven points adrift of second-place Atletico Madrid. Despite their few Champions League goals scored (five), Brugge have thrived domestically courtesy of a young attack featuring Wesley, Siebe Schrijvers, and Arnaut Danjuma Groeneveld, and attacking midfielder Hans Vanaken.
Chelsea have played Brugge on four occasions in the 1971 and 1995 Cup Winners' Cup, while Arsenal have yet to face the Belgians in European competition.
Inter bottled it. With progression to the last-16 a near certainty, Inter lost to Tottenham before slumping to a 1-1 draw against PSV to book a Europa League berth. Luciano Spalletti's charges have gelled after a slow Serie A start stemming from a series of summer signings, and Mauro Icardi continues to be a source of meaningful late goals, with all four of his European tallies this season coming after the hour mark.
The Blues and Nerazzurri have played twice competitively, with Inter taking the 2009-10 Champions League last-16 clash 3-1 on aggregate. Arsenal and Inter have also only played twice, splitting the home-and-away ties in the 2003-04 Champions League group stage during the Gunners' Invincibles campaign.
Like Serie A brethren Inter, Carlo Ancelotti's Napoli appeared poised to advance before sliding from first to third in Group C after Matchday 6 defeat at Liverpool. And like Inter, Napoli are likely to contest bridesmaids' status in Italy, but instead of relying on one source for goals, Dries Mertens, Lorenzo Insigne, and Arkadiusz Milik spearhead a trident attack.
Chelsea faced off twice in the 2011-12 Champions League group stages with Napoli, with each side registering a win. Arsenal faced Napoli in the following year's tournament, and again, both teams collected a victory.
Galatasaray, the record 21-time Turkish champs, secured a Europa League spot despite losing their last three Champions League matches, and prospective opponents will be chomping at the bit to play the Istanbul outfit. Galatasaray currently sit seventh in the Super Lig, but just a point adrift of second place. And after Fatih Terim led the club to a stellar second-half run last season, the likeable gaffer's veteran squad and his preferred 4-2-3-1 set up could be a handful.
Arsenal will embrace a chance to again face Galatasaray after the Turkish giants defeated them in the 1999-2000 UEFA Cup final. The Gunners have beaten Galatasaray by a 4-1 scoreline in each of their last two meetings. Chelsea have never lost to Galatasaray in four previous matchups.
Portugal's most-decorated domestic side have fallen on hard times on the continent, though Rui Vitoria's lot have some decent showings in Europe's second competition after losing the 2013-14 Europa League final to Sevilla. Ageless wonder Jonas and Swiss international Haris Seferovic lead Benfica up top, while Pizzi pulls the strings in a central midfield role. Defending counter attacks and protecting leads have been issues for the Lisbon locals.
Chelsea have played Benfica three times since 2012, winning all three matches, while Arsenal have only faced the Eagles twice, pairing a loss with a draw in the 1991-92 European Cup.
European regulars Shakhtar Donetsk narrowly missed out on Champions League progression thanks to Nabil Fekir's equalizer for Lyon on Matchday 6, and after conceding 16 times in six group matches, it was a fitting ending. Semi-finalists in the 2015-16 Europa League and one of two Ukrainian sides to win a continental tournament, Shakhtar are dominant domestically atop the Ukrainian division with a plus-34 goal differential courtesy of 14-goal man Moraes.
The north London outfit and Shakhtar have split four meetings in Europa, with the last coming in the 2010-11 Champions League group stage. Henrikh Mkhitaryan derby is on the cards. Chelsea and the Ukrainians were grouped together in the 2011-12 tournament, with both sides registering one-goal victories.
Czechs Viktoria Plzen have plenty to be proud of after nearly taking second spot in Group G from Roma, who they beat 2-1 on Matchday 6 at the Doosan Arena. Victories in their last two Champions League outings should boost the confidence among Pavel Vrba's squad, as should a nine-match unbeaten run in the Gambrinus League. Forward Michal Krmencik is the focal point, and midfielder Ales Cermak is the key creative force.
Neither Chelsea nor Arsenal have faced Plzen in a competitive fixture,
On paper, La Liga luminaries Valencia would provide a matchup both London sides want to avoid. In reality, Los Che have been poor this year, both in Spain and in the Champions League. Marcelino's lot gifted Manchester United a last-16 spot thanks to a limp attack, something that has also plagued the club domestically, with just a dozen goals scored in 15 matches for the 15th-placed side. However, Valencia doesn't concede much either, posting even goal differentials in both competitions.
Arsenal and Valencia have played five continental clashes, including the 1979-80 Cup Winners' Cup final that the Spaniards won on penalties. Valencia has never lost to Chelsea, winning three Champions League matches to go with a treble of draws.