1. Costa Rica searching for old winning formula
Costa Rica surprised everyone four years ago by making it all the way to quarterfinals in Brazil. However the momentum from that unlikely run slowed long ago and Los Ticos have won just two of seven friendlies since securing a World Cup spot.
The Central Americans' first outing here will be against Serbia on Sunday in the southwestern city of Samara. Real Madrid goalkeeper Keylor Navas is the team's brightest star and he conceded just eight goals in 10 matches during the second stage of qualifying.
2. Milinkovic-Savic to show his wares
Serbia have also been less than convincing of late. Mladen Krstajic's side have won three of six friendlies since qualifying for Russia with a final-day victory over Georgia.
Lazio midfielder Sergej Milinkovic-Savic might have added incentive to perform well amid reports that he is being monitored by Real Madrid and Manchester United.
3. Germany start quest for back-to-back glory
Germany are hoping to become the first team to defend their title since Brazil in 1962. The current side has many players that were part of the victorious 2014 squad, including influential midfielders Toni Kroos and Mesut Ozil and goalkeeper Manuel Neuer.
The team's form going into the tournament hasn't been great, with a 2-1 loss to Austria and an unconvincing 2-1 win over Saudi Arabia earlier this month. They will get their World Cup campaign underway with a clash against Mexico at Luzhniki Stadium in Moscow.
Mexico have won only one of their 11 matches against Germany and that was way back in 1985. The only time the teams have met in Russia was in the semifinals of last year's Confederations Cup, when Germany won 4-1. The Tri boast a dangerous attack, led by Javier Hernandez and Raul Jimenez, even if the pair's recent club form has been less than spectacular.
4. Brazil regain swagger
Brazil will start the tournament with a clash against Switzerland in Rostov-on-Don. The Selecao are on a roll, having lost just once in 20 games since coach Tite took over from Dunga in June 2016. Unlike in 2014, this Brazil squad boasts world class players all over the pitch, particularly in the final third, where a fit-again Neymar, Gabriel Jesus and Philippe Coutinho will instil trepidation in rival defences.
Much has been said about Brazil's 7-1 loss to Germany in the semifinals four years ago, but there is a sense that Tite has put that ghost to rest and that this team is perhaps ready to write a new chapter in the country's storied football history.
5. Switzerland to sit back
Switzerland will be no pushovers for Brazil, or any other rival. Vladimir Petkovic's side won nine games in a row in qualifying and were also unbeaten in four pre-World Cup friendlies, including a 1-1 draw with Spain.
There is little to suggest that Petkovic will stray from his tried and trusted game plan based on sitting deep and hitting teams on the counter. Their most potent attacking threat is Xherdan Shaqiri, who has scored or set up five of the team's last six goals in major tournaments.
