Manager Jose Mourinho is confident Chelsea have assembled a squad capable of winning the Barclays Premier League next season - but also knows any of the title hopefuls could also easily end up fifth.
The Blues have moved quickly in the summer transfer market, bringing in Cesc Fabregas before the World Cup, and have since added fellow Spaniard Diego Costa and also defender Filipe Luis from Atletico Madrid, as well as promising 19-year-old midfielder Mario Pasalic from Hajduk Split.
Mourinho, however, understands all too well each of the other leading sides have also strengthened their armoury, while Manchester United are expected to recover and challenge again under new manager Luis van Gaal.
"Last year, if you had asked me in July, I would never have said Man United would be outside the top four. This season I will tell you one (to miss out) and I have a big percentage of making a mistake," said Mourinho, who is an ambassador and pundit for BT Sport next season and took part in a Q&A session at BT Tower in central London on Friday night.
"There were good teams last season and there will be better teams this season because everyone is investing.
Chelsea: Potential summer transfer targets
Chelsea: Potential summer transfer targets
1/9 Paul Pogba
Former Manchester United midfielder was spotted in west London setting the rumour mill into overdrive. The classy French midfielder, still just 21, impressed at the World Cup and has been linked with a blockbuster £60m move to Stamford Bridge, despite the recent arrival of Cesc Fabregas. However, he is also linked with a move to Manchester City as a potential replacement for Yaya Toure.
2/9 Adrien Rabiot
The talented teen put clubs in Europe on alert after rejecting a contract offer from Paris Saint-Germain. Chelsea made a move for the Frenchman in January and have gone back in for him, even though he is highly rated by PSG coach Laurent Blanc.
3/9 Sami Khedira
The German midfielder missed five months for Real Madrid's season with a knee injury and has played just 15 games this term. With Madrid reportedly interested in signing new players in central midfield, Khedira's future at the Bernabeu could be at an end. The 27-year-old is interesting Arsenal, but should Chelsea go in for him too, they would be getting a player that Mourinho knows well and real quality in front of the back four, not dissimilar to club legend Claude Makelele.
4/9 Yaya Toure
An outside bet, of course, but with all the drama surrounding the Toure and Manchester City recently, Chelsea could swoop. A powerhouse of a midfielder with a surprisingly deft touch and devastating skill at the dead ball, the 31-year-old would be huge assent to any team in the world. Toure cost City £24million in 2010, so any offer would have to huge from Chelsea if they are to persuade the Sky Blues to sell to a title rival.
Tottenham's summer signing hasn't quite lived up to the form he reached in Brazil's Confederations Cup victory in 2013 and struggled at the World Cup, but he has still performed well enough to have Chelsea and Real Madrid reportedly interested in acquiring his services. The 25-year-old would fit in well at Stamford Bridge given the Blues' strong Brazilian contingent already. Paulinho had a mixed first season in the Premier League, scored six goals with three assists last season and not the return Spurs were hoping for, and the lure of Champions League football could persuade the midfielder to switch London clubs.
6/9 Fabio Coentrao
With Ashley Cole having joined Roma and Ryan Bertrand also likely to leave, Jose Mourinho will be in need of a quality, experienced left-back and one possibility is Real Madrid's Coentrao. The 26-year-old came close to joining Manchester United in January and is likely to lose his starting place at Madrid when Marcelo is fully fit again next season. Carlo Ancelotti denies any rumours that the Portuguese defender will leave but if the right offer were to be made by Chelsea, he could be on his way to London and nail down a starting role with ease.
7/9 Edinson Cavani
After a season of playing in the shadow of Zlatan Ibrahimovic at PSG, Cavani looks likely to leave the French side after just one year and become the main man at an English club next season. Chelsea remain interested in the Uruguayan but Chelsea are despite a deal for Diego Costa already complete, but may face competition from Manchester United. The 27-year-old cost PSG €64.5million last summer, so any offer from Mourinho would take a large slice of his funds but with his striking power and goals an almost guarantee, it could be a risk worth going for.
8/9 Radamel Falcao
The Colombian striker did not regain fitness in time for the World Cup but it has given him a good chance to weigh up his future. Seemingly always in transfer rumours despite his €60m switch to Monaco last summer, Falcao is a long-term target of the Blues, though Diego Costa has filled the previously vacant No 9 role. The 28-year-old lit up La Liga during his two seasons with Atlectico Madrid but, mainly because of injury, has failed to live up to his price tag in France. If unrest reports are true, Chelsea could attempt an offer.
9/9 Raphael Varane
Reportedly unhappy at Real Madrid due to his low wages in comparison to his team-mates, the centre back has been linked with a move away. Chelsea are reportedly one of the clubs interested in the France international with Jose Mourinho seeing him as a long-term replacement for John Terry.
"A few years ago you make a team to be champions and most probably you are champions. Now if you make a team to be champions, you try to finish in the top four."
Mourinho added: "Why I like the Premier League so much is that at this moment, nobody knows who is going to win the title.
"I know that we want to and I know that we can, but it is the kind of competition where I can't say.
"At this moment, I think between us, Liverpool, Arsenal, Man United, Man City - who is going to be first, who is going to play in the Europa League, I don't know."
Mourinho maintains it took him only 20 minutes to convince Fabregas to sign from Barcelona - and reckons the former Arsenal captain never wanted to move back to his old club.
Arsenal had first option to bring Fabregas back to the club he left in 2011, which manager Arsene Wenger passed up as he pursued other targets.
Mourinho, though, feels Stamford Bridge was always the midfielder's preferred destination.
"I spoke with him 20 minutes. I think he really wanted to come to us," he said.
"As you know, Arsenal had an option where they could interfere, but I think he was not open to that, I think he was very, very much in our direction, so it was an easy job for me."
Mourinho indicated the Blues' chequebook was now closed.
"I have to say my club did a fantastic job, and not just because of what we bought, but because we did it in almost record time. The transfer market closes 31 August and we close our market on July 19. We finished the market today," he said.
"The club did fantastic, we knew the targets, we knew the players and the club attacked them and their clubs at a very early stage.
"We got exactly what we need and what we want. The squad is one which I like very much and I look forward to starting the season."
Mourinho added: "I don't think so (sign any more players). The market is open, but we are so happy with what we have."