Even for a club of Barcelona's standing, the start to their Champions League campaign looked difficult with Juventus - who knocked the Spaniards out of last season's competition - first up before a tricky trip to face Sporting Lisbon in Portugal.
The Blaugrana have made easy work of it so far, though, with Lionel Messi inspiring his side to a 3-0 win over Juve on matchday one before a Sebastian Coates own goal was enough to come back from Lisbon with a narrow 1-0 victory.
Another win this Wednesday would mark a big step towards the last 16 for Barcelona, but they come into the match having slipped up for the first time since the Super Cup defeats to Real Madrid back in August.
The other major Madrid club were responsible for that slip-up as Atletico held Barca to a 1-1 draw at the weekend, ending their nine-match winning streak and 100% start to the La Liga season in the process.
Valverde's side remain four points clear at the top of the pile domestically, though, and most would still make them favourites to wrest the title back from Real Madrid this season.
If they can do the same on the European front then it would make for a memorable debut campaign for Valverde, and if Barca need testament to his ability to win trophies then they need only ask Wednesday's visitors, with the Spaniard having led Olympiacos to three league titles during his two spells in charge.
Anything other than a victory over his former club would be a surprise considering Barcelona's home form so far this season, where the Spanish giants have won their last five games while scoring 19 goals and conceding just one in the process.
Barca are unbeaten in their last 22 Champions League matches on home soil stretching back to May 2013, winning 20 of those including the 3-0 triumph over Juventus on matchday one.
Couple that with a 100% record in six previous home games against Greek opposition and there only looks like being one winner on Wednesday as Barca bid to reach the Champions League knockout stages for the 14th year in a row.
Recent Champions League form: WW
Recent form (all competitions): WWWWWD
Olympiacos may be forgiven for pining for a return to Valverde's time in charge of the club right now, with the Greek giants having made a poor start to the season both domestically and abroad.
In fairness, their Champions League chances always looked slim when they were drawn in the same group as Barca and Juventus, but defeat at home to Sporting Lisbon on matchday one - a game they were 3-0 down in by half time - was an early blow to their hopes of claiming third place and Europa League qualification.
A 2-0 defeat to Juventus in their last Champions League outing means that they travel to Camp Nou bottom of Group D without a point to their names at the moment, although their main concern right now will be their domestic form.
Olympiacos had won just one of their previous seven matches across all competitions prior to a late 4-3 win over Panionios on Saturday, including a run of three straight defeats which made for their worst spell of form since February 2009.
The seven-time defending Super League champions have won just three of their opening seven league outings this season, leaving them seven points worse off than at the same stage last term.
Olympiacos travel to Camp Nou looking for back-to-back wins for the first time since August, and although they have won three of their last five European away games including qualifiers, hopes will not be high of improving that record in midweek.
Saturday's win over Panionios was their first on the road in any competition since August, while they have also lost each of their last five visits to Spain in a run which stretches back to a goalless draw with Deportivo La Coruna in 2004-05.
Indeed, Olympiacos would need to create a small slice of history if they are to pull off a major shock in this match having never won in 14 previous away games against Spanish opposition, drawing twice and losing 12 of those trips.
Recent Champions League form: LL
Recent form (all competitions): DWLLLW
Barcelona have no new injury concerns for this match, meaning that Ballon d'Or nominees Messi - who has 17 goals in 16 games for club and country this season - and Luis Suarez will once again start up front.
Valverde must decide whether to stick with a 4-4-2 formation in the continued absence of Ousmane Dembele, although Gerard Deulofeu will be hopeful of a recall should Barca opt for a more attacking lineup.
Karim Ansarifard will be hopeful of leading the line once again for Wednesday's visitors, having scored twice during Saturday's victory against Panionios.
Barcelona possible starting lineup:
Ter Stegen; Roberto, Pique, Umtiti, Alba; Rakitic, Busquets, Iniesta; Deulofeu, Suarez, Messi
Olympiacos possible starting lineup:
Proto; Koutris, Cisse, Nikolaou, Figueiras; Odjidja-Ofoe, Romao, Pardo, Fortounis, Seba; Ansarifard
Head To Head
These two sides have never faced each other in a competitive fixture before, although Barcelona do have a formidable record against Greek opposition.
The Blaugrana have won nine of their 12 matches against Super League teams, including all six of their home games while scoring 26 times and conceding just three.
Barca are unbeaten in their last seven meetings home and away, winning each of their last three all of which have come against Panathinaikos and all of which saw Messi get on the scoresheet.
We say: Barcelona 4-0 Olympiacos
It is difficult to see anything other than a comfortable home victory for Barcelona in this one. Valverde's side have been in excellent form this season, particularly at home, while they are taking on an Olympiacos side in worse shape than they have been in for some time.