We have reached the business end of the World Cup, a crucial stage when preparing our Fantasy sides for the quarter-finals.There are four free transfers available before Thursday’s 9pm UK deadline (4pm ET), with the maximum players per country increasing to five.So, with the player pool dwindling to just eight teams, how should we be preparing?Captain conundrumPicking a captain will be fun, with France, Spain, England and Argentina the favourites in their quarter-finals.The obvious captain pick for the opening game is Kylian Mbappe ($10.5m). The France striker is impossible to ignore, with seven goals and two assists in this tournament, returning a goal involvement in each of his appearances.For Spain, expect Lamine Yamal ($10m) to punish an attacking Belgium left side that could leave space to attack. The 18-year-old has not hit top form yet, with just one goal, but his time could come.There’s flexibility on Saturday when England take on Norway, with Harry Kane ($10.5m) three points ahead of Jude Bellingham ($8.3m). The England captain is on penalties, too.While England are the favourites, you’d expect Erling Haaland ($10.5m) to cause some problems, having scored in his four appearances at the tournament.Haaland is one behind Lionel Messi ($10m) on eight goals and the Argentina forward will be everyone’s last roll of the captaincy dice for their clash with Switzerland. He is the only player to score in all five of his nation’s games (Haaland was on the bench for Norway’s 4-1 defeat against France).The threshold for captaincy from Mbappe will be around the 12-15-point mark, declining to 9-10 points by the time we get to Saturday's games.Stick or twist strategy is becoming increasingly difficult to call.Patience is keyWe will have team news before the deadline for France and Morocco.This will give managers crucial information on the availability of Morocco's Ismael Saibari ($6.8m), who was substituted after 22 minutes in the 3-0 win against Canada with a hamstring injury.The question marks in the France attack are at left-back and left-winger, where Lucas Digne ($5m) and Bradley Barcola ($8m) got the nod last time out.Backers of Digne were rewarded with a scouting bonus in the 1-0 win against Paraguay, but expect his ownership to rocket from 3.9 per cent over the threshold if he's named in Didier Deschamps' side.In the World Cup Fantasy format, points hits for extra transfers cost managers three points, rather than the four we usually see in Fantasy Premier League.With the ability to make manual substitutions, having a full playing 15 becomes highly valuable, so I wouldn't be against hits to remove eliminated players.One goalkeeper is probably enough for this round, especially if you have a premium goalkeeper such as Emiliano Martinez ($5m).Those activating the Clean Sheet Shield for this round also get greater flexibility, allowing managers to go without a full complement of goalkeepers or even defenders. I was highly disappointed with the Clean Sheet Shield in the round of 16 — none of my defenders conceded exactly one goal to trigger it.Those who still have this chip may be wise to activate it now. The same could be said for the Wildcard, given just four free transfers, while the Qualification Booster should be more fruitful now than at the latter stages.With just two bites of the captaincy cherry reserved for the semi-finals and finals, it's important to remain patient with the Max Captain chip. I'll be waiting for the final for that one.Who to target?Four free transfers will be critical for this stage of the competition, especially given some heavily backed picks were eliminated in the round of 16.Brazil were the surprise losers, with star man Vinicius Junior in over 30 per cent of sides. Popular defensive picks from Portugal, Colombia and the United States also departed the tournament.Add into the mix injuries for Morocco's Saibari and Switzerland's Johan Manzambi ($5.6m), plus competition at left-back for Argentina between Facundo Medina ($4m) and Nicolas Tagliafico ($4.3m), and we are in a tricky spot.There are no easy games at this stage of the competition, and there's enough talent still in the pool of remaining players that I'd avoid going with five players from any side.Argentina will carry the highest clean-sheet hopes against Switzerland, with Lisandro Martinez ($4.6m) and Nahuel Molina ($4.4m) the wisest investments, especially if Molina can stay under 5 per cent ownership.I'd also back the Spain defence, who still haven't conceded a goal in the tournament, with a double or triple up attractive against Belgium. Marc Cucurella ($5.1m) is now 42.9 per cent owned, but you can add Aymeric Laporte ($5.5m) or Pedro Porro ($5.5m) alongside him.Marc Cucurella and Pedro Porro both offer goalscoring threat and clean sheet potential (Frederic J. Brown / AFP via Getty Images)In attack, the go-to replacement for Vinicius Jr should be Bellingham, who produced a 14-point haul against Panama and a 15-point return against Mexico.Scouting bonus…You could look to chase the scouting bonus with three-per-cent-owned Anthony Gordon ($7m) too, who should keep his place after his impact substitute performance against DR Congo with two assists and a penalty won against Mexico.He played the full 90 minutes in that win, having been rotated plenty earlier in the tournament on the England left with Marcus Rashford. He's lighter on the budget, too.Argentina's Enzo Fernandez ($7.5m) scored the winner against Egypt, but remains just 3.4 per cent owned. Other than being rested against Jordan, he's played every single minute for the defending champions.Morocco's Brahim Diaz ($6.4m) is easy on the budget and just under the 5 per cent threshold, with two assists in the 3-0 win against Canada. The underdog differentials are easier to back earlier in the round, before switching to other assets with those manual substitutions.