St Petersburg: The liveliest selection debate swirling around Brazil's national team heading into the World Cup has become more intense one game into the tournament.
Should it be Gabriel Jesus or Roberto Firmino in the lone-striker role?
A favorite of Tite's since the coach took charge in June 2016, the 21-year-old Jesus started Brazil's opening group game - a 1-1 draw against Switzerland - but struggled to impose himself.
He made way in the second half, as usual, for Firmino, who made more of an impression in the 11 minutes he had on the field in Rostov and nearly scored a late winner from a header.
While Jesus is coming off a mixed first full season at Manchester City, the 26-year-old Firmino enjoyed the best year of his career for Liverpool and was one of the team's key figures in its run to the Champions League final.
Now that he has added goals to his consummate all-round game - he scored 27 in all competitions for Liverpool this season - the hard-working Firmino could yet be the better option for a game Brazil needs to win.
There are clear differences between the strikers: Jesus is quicker and plays on the shoulder of the last man, while Firmino drops deeper and links up play better. Against a Costa Rica team that is likely to sit back and attempt to soak up pressure, there might be less space for Jesus to get in behind the defense.
Indeed, there is even more focus on Brazil's forward line ahead of the game in St. Petersburg given the concerns over the fitness of Neymar, who limped out of a training session on Tuesday because of pain in his right ankle - apparently sparked by persistent fouling from Switzerland's players in the team's opening match in Rostov. The forward has recently returned after three months out with a foot injury.
Costa Rica opened Group E with a 1-0 loss to Serbia, conceding the goal from a direct free kick.
"I watched part of their game against Serbia," said Brazil midfielder Philippe Coutinho, the team's scorer against Switzerland, "and it was decided on a set piece. It's a team that likes to play. We will stick to our game, playing with joy and audacity."
The Brazilian federation attempted to allay concerns over Neymar's condition, saying the injury is not serious, but it is clearly a worry for the five-time world champions. He was visibly in pain during Tuesday's session, having been seen limping after the Switzerland game.
If Neymar is ruled out, pacy winger Douglas Costa would be a possible replacement. Firmino could also play out wide, in a move that would keep Jesus in a central position.
Campbell to start?
Costa Rica topped its group and surprisingly reached the quarterfinals at the World Cup in 2014 by being compact, hard to break down, fearless and playing on the counterattack. Judging by the Serbia game, things don't look much different in the 2018 edition.
Los Ticos ultimately were undone by a moment of technical brilliance by Aleksandar Kolarov and held their own for most of the match, but whether the second-oldest squad at the World Cup has it in them to hold off Brazil is another matter.
Coming off another injury-hit season, this time on loan at Real Betis in Spain, forward Joel Campbell provided a spark as a 67th-minute substitute against Serbia and will be pushing for a start.
There could be a well-known face watching the match at St. Petersburg Stadium: Sepp Blatter is expected to be in attendance.
The former FIFA president is banned from official football duty until October 2021 for financial misconduct during this 17-year rule at the governing body, and has rarely flown in recent years since American and Swiss investigators unsealed sweeping investigations in May 2015.
He is in Russia, though, fulfiling a two-year-old invitation from the country's president, Vladimir Putin....