Porto and Shakhtar Donetsk do battle in the UEFA Champions League having made bright starts to their league campaigns.
Europa League and Liga Sagres champions Porto have a 100 percent record in the league after winning four from four, netting 12 goals and conceding just three.
Star striker Hulk and Colombian James Rodriguez have both scored three times, with the latter filling the void left by the departure of Radamel Falcao to Atletico Madrid.
Shakhtar Donetsk have been just as impressive in the Ukrainian Premier League, recording seven wins and two draws in nine outings.
That includes scoring 24 times and conceding just six in a bright start to their title defence.
Porto coach Vitor Pereira, who took over after the departure of Andre Villas-Boas to Chelsea, is passionate about their European adventure, beginning with progressing from Group G.
Seeing Porto playing in the Champions League is something special, Pereira told uefa.com.
I get goose bumps when I hear the UEFA Champions League anthem.
A positive result for Shakhtar Donetsk at the Estadio do Dragao could give them a massive advantage.
The Ukrainians reached the quarter-finals of the tournament last season before being eliminated by eventual champions Barcelona.
These two teams are expected to progress from this group, but making a good start would be helpful in avoiding the pressure later.
In the other game, Russian outfit Zenit Saint Petersburg will travel to meet Cypriots APOEL.
Zenit striker Aleksandr Kerzhakov has netted 13 goals in 17 league games this season and will be a danger up front for the 2008 UEFA Cup winners.
Both of these sides are likely to battle to get through the group, making their clashes against each other very important.