Barcelona legend Gerard Pique has singled out Marcus Rashford as the biggest surprise in La Liga so far this season following his move from Manchester United, though the former defender admitted that Real Madrid superstar Kylian Mbappe is currently operating "on another level" compared to the rest of the competition. The Frenchman has made a blistering start to the campaign in Spain, averaging a goal a game for Xabi Alonso's team.The current La Liga campaign has been defined by a fascinating battle between established superstars and fresh faces looking to make their mark. While Kylian Mbappe is now firmly entrenched as the face of Madrid following his move in 2024, the arrival of Rashford in Catalonia this summer has added a new dynamic to the title race.The England international joined Hansi Flick's side on a season-long loan from Manchester United in July, looking to revitalise a career that had stalled at Old Trafford. His impact has been immediate, with his pace and direct running providing Barcelona with a different dimension in attack as well as six goals - two in La Liga and four in the Champions League. It is a transformation that has caught the eye of Pique, who knows exactly what it takes to succeed in Catalonia.Speaking in an interview with Sport, the former Barcelona captain was asked to identify the players who have impressed him most this term. Pique wasted no time in highlighting the English forward's seamless adaptation to Spanish football.Asked who has surprised him most this season, Pique picked the 28-year-old Englishman, saying: "Rashford. I think he had a very good start, now let's see how he continues. He scored two goals in the match against Newcastle, he has contributed and helped a lot since the beginning."However, despite his allegiance to the Blaugrana, Pique could not ignore the elephant in the room. When discussing the absolute elite performers in the league, he conceded that Real Madrid's number nine sits alone at the top of the mountain. After all, the Frenchman won the league's top scorer prize on his debut season and has followed that up with a whopping 16 goals in as many La Liga games this term, despite Madrid struggling for consistency and falling behind Barcelona in the top-flight. He has also netted an incredible nine in just five Champions League matches."Also Mbappe, he is on another level and not just in goals, but also in how he looks," Pique admitted. "I think he is sharper than ever."The former defender also tipped his cap to rivals Atletico Madrid, noting the contributions of their Argentine contingent. "Looking at other teams, in Atletico you have Giuliano Simeone, who is doing very well, Julian [Alvarez], who is a differential player," he added. "I think in La Liga there has not been any big surprise and that everything is being quite expected."Looking for smarter football bets? Get expert previews, data-driven predictions & winning insights with GOAL Tips on Telegram. Join our growing community now!Pique’s comments validate what has been a rejuvenating few months for Rashford. There were significant doubts over whether the 28-year-old could adapt to the technical demands of La Liga, but he has answered his critics emphatically. Pique highlighted his pivotal Champions League performance earlier against Newcastle, in which he scored twice to seal a 2-1 win. He has also provided six assists in the domestic competition and a further one in Europe.For a player who looked lost at United under Ruben Amorim, Rashford has found a new lease of life under Flick. His versatility across the front line has been crucial for Barcelona, allowing them to rotate Lamine Yamal and Robert Lewandowski without a drop in quality.While Rashford has been a pleasant surprise, Mbappe has been an inevitability. Now fully settled in his second season in Madrid, the Frenchman has evolved into the complete leader of the Los Blancos attack.Pique’s observation that he looks "sharper than ever" is a frightening prospect for defences across Europe. Having already lifted the Champions League in his debut season, Mbappe appears determined to chase down individual records this term. His dominance is such that even the staunchest Barcelona icons are forced to acknowledge his supremacy.For Rashford, the challenge is now consistency. As Pique noted, "let's see how he continues." With reports suggesting Barcelona have a purchase option in the region of €30 million for next summer, the Englishman is effectively playing for his long-term future. A strong second half of the season could seal a permanent exit from Old Trafford.Meanwhile, Mbappe and Real Madrid face a defining week with a Champions League clash against Manchester City. With the team suffering from a defensive injury crisis, the onus will once again be on their French superstar to provide the "differential" quality Pique so admires.