The pair are locked on 13 points at the top after much-fancied Belgium strolled to a 2-0 win in Macedonia on Friday when Croatia were celebrating victory over their neighbours.
Inspirational playmaker Luka Modric said the Croatians would have more than just his former Tottenham Hotspur team mate Gareth Bale to worry about against Wales, who beat Scotland 2-1 away on Friday to lie third.
"One player can't win games by himself and we know that we will be up against a good team who will be roared on by a passionate home crowd," Modric told Croatian media.
"Only a win against the Welsh will do for us, otherwise the win against Serbia will lose a lot of its gloss and we risk falling behind in the battle to win the group."
Wales midfielder Aaron Ramsey was sent off against Scotland so misses out while Bale was substituted at halftime but expects to start in Swansea.
"Nothing wrong with my ankle. I came off due to the stomach virus. Should be OK for Tuesday," he said on Twitter.
Croatia coach Igor Stimac has said he will make at least three changes to the starting lineup that brushed Serbia aside in the first half and then held out comfortably in the second.
Veteran striker Ivica Olic, who was at the heart of Croatia's win after scoring one goal and setting up the other, is likely to be one of the players rested after rolling back the years against the Serbians.
Everton forward Nikica Jelavic should replace the 33-year-old while teenage midfielder Mateo Kovacic, whose mature performance in Zagreb impressed both Stimac and Serbian counterpart Sinisa Mihajlovic, could make way for Ognjen Vukojevic.
Midfielder Josip Radosevic or Eduardo da Silva could break into the starting lineup instead of Niko Kranjcar, who picked up a knee injury against the Serbians and is likely to be out of action for up to four weeks.
Defender Josip Simunic is also nursing a knock but the Croatia doctors have cleared him to play against Wales, although Stimac may be tempted to rest him and give Domagoj Vida a chance.
Wales: Boaz Myhill; Samuel Ricketts, Ben Davies, Ashley Williams, Chris Gunter; Andrew King, Joe Ledley, Jack Collison, Gareth Bale; Craig Bellamy, Hal Robson-Kanu
Croatia: Stipe Pletikosa; Darijo Srna, Vedran Corluka, Josip Simunic, Ivan Strinic; Ivan Rakitic, Ognjen Vukojevic, Luka Modric, Eduardo da Silva; Mario Mandzukic, Nikica Jelavic
Referee: Luca Banti (Italy)