UEFA Champions League Group G preview: Celtic aim for top spot
Celtic could take surprise control of Group G if results go their way during UEFA Champions League action against Benfica on Tuesday.
Fresh from their historic victory over Barcelona on matchday four, the Scottish Premier League champions are in a solid position to qualify for the knockout phase of Europe's most illustrious club competition.
Neil Lennon's side have taken seven points from four matches, while Barcelona top the group with nine points.
Victory in the Portuguese capital, together with a Barcelona defeat, would not only guarantee qualification but it would see the 1967 European Cup winners go top.
And their form suggests another win could be on the cards, with the Glasgow giants unbeaten in six competitive fixtures.
However, Celtic will be facing a Benfica outfit desperate to keep their qualification hopes alive.
Despite Benfica making an unbeaten start in Portugal's top flight, Jorge Jesus' men have struggled to transfer that form into the Champions League.
The Lisbon-based club occupy third position, with one win, one draw and two defeats in four outings.
And with Barcelona their opponents on matchday six, Benfica are aware a loss could spell the end of their Champions League campaign.
In Group G's other fixture, Spartak Moscow welcome Barcelona to Russia.
Spartak may languish at the foot of the table but that is not a true reflection of how the Russian side have performed this year.
Unai Emery's men were unfortunate to taste defeat in their opening match against Barcelona, falling to a 3-2 loss at Camp Nou despite leading 2-1.
Spartak went on to lose two of its next three games but never looked out of place.
However, they will find the going tough on Tuesday with several players set to miss out.
Captain Sergei Parshivlyuk, leading striker Welliton, Diniyar Bilyaletdinov, Romulo, Aiden McGeady, Nicolas Pareja and Artem Dzyuba will watch from the stands, while all three goalkeepers are nursing injuries.
As for the Spanish giants, nothing less than a win would be expected by Tito Vilanova as they aim to avenge their defeat to Celtic.
Led by the prolific Lionel Messi, Barcelona continues to dominate in the attacking third but it is their defence which is causing the most concern.
Club captain Carles Puyol has stated publicly the defence needs to improve, highlighting the team's vulnerability at set-pieces.
"We have had a fantastic start," he said.
"Although we need to sort out the defensive situation and we are working on that.
"Generally the problems have been on set-plays where we have been caught out."