In front of a crowd of 57,748 at Miami’s Sun Life Stadium, Chelsea completed their US summer tour Saturday night with a 1-0 loss to AC Milan. Despite the vast majority of fans cheering Chelsea inside the humid stadium, the Blues failed to create enough clinical chances to turn the match in their favor.

The match itself was largely uneventful. Chelsea is still trying to find their stride as well as their fitness this preseason. Romelu Lukaku is tall, skillful and strong, but at just 19 years-old and with too few games at Chelsea so far in his career, the Belgian striker is nowhere near as dangerous as Didier Drogba was. If Lukaku is in open space, he’s got the speed to attack at defenses. But when he receives the ball and is marked closely by tight markers, Lukaku doesn’t have the physical strength or prowess yet to shake off defenders like Drogba did. By himself up front, Lukaku will continue to have a difficult time. What he needs is a striking partner who can work closely with him to cause more of a threat.

At the same time, Fernando Torres — in just his first match back for Chelsea after returning from Euro 2012 duty — looked understandably rusty. Torres still plays with the hunger and desire, but lacks the perfect touch, often losing control of the ball under his own feet. Just as we saw late last season, he’s also missing that world-class striker instinct in front of goal. Instead of firing a shot at goal at the perfect moment to increase his goalscoring chances, he’s either taking one or two seconds too much time on the ball, choosing to dribble when he should shoot, or taking an extra touch on the ball that gives defenders an opportunity to close him down. Torres, while a magical player, still has a lot of room for improvement to get back to his top form.

Yet, this is still preseason. Chelsea players are obviously trying to reach their peak fitness as well as learning to play together as a team. But time is quickly running out for Roberto Di Matteo’s side. Chelsea has only one more preseason friendly remaining before the Community Shield on August 12.

The weaknesses up front for Chelsea are all too apparent. Yes, Daniel Sturridge is on Team GB duty, but Chelsea needs to seriously consider trying to either wrap up the signature for Porto striker Hulk, or to make another signing soon. It’ll undoubtedly ruffle the feathers of Torres, but Chelsea needs to have a Plan B. The Blues can’t simply rely on either Torres, Lukaku or Sturridge to score on a continuous basis each week. All three are gifted, but each player has his weaknesses.

It’s not just up front where Chelsea has been exposed. Watching them play Saturday night, I saw once again how Chelsea is so slow when moving the ball forward in attack. Except for the game against Seattle where Lukaku and Josh McEachran linked up to tear Seattle apart at times, Chelsea has looked very slow and methodical against Paris Saint-Germain, MLS All-Stars and now AC Milan. There’s still much work to be done there.

On top of that, Marko Marin is going to have a difficult time adjusting to the Premier League. When he’s dribbling and has space, he’s wonderful at weaving his way through defenders. But when it’s a 50-50 ball, the German player is so tiny and skinny that it’s easy for him to be knocked off the ball. Based on what I saw Saturday night, he certainly needs to hit the gym more often to bulk up.

On the plus side, Chelsea’s man of the match Saturday night was Eden Hazard. The Belgian attacking midfielder was speedy, dangerous on his attacking runs toward the opposition’s penalty box and, most important of all, wonderful in his off-the-ball movement, often finding ways to move into open spaces and giving his fellow midfielders plenty of options to pass to him. He’s the one new bright spark in this Chelsea side, and he’ll certainly be a joy to watch in this new season.

Preseason performances can often be deceiving, but I’m particularly worried about Chelsea’s first few weeks of the Premier League season where they will need to significantly improve their game to make a good start to the new season. Their pre-season squad was missing several players to Olympic duty, but even with the players at their disposal during this US summer tour, they should have done much better. The tour was a success off the field, but on it, Chelsea has much work still left to do in the transfer window if they want to mount a serious challenge for the Premiership title.