By Alan Baldwin
BARCELONA (Reuters) - Nico Rosberg has an even bigger battle than last year on his hands because Formula One champion team mate Lewis Hamilton is at the peak of his powers, according to Mercedes technical head Paddy Lowe.
"I think Lewis is performing, really, at the top of his game," Lowe told reporters at the Spanish Grand Prix, where Hamilton will be chasing his fourth victory in five races on Sunday.
"I’ve worked with Lewis actually throughout his Formula One career and I would say at the moment he’s really at his peak -- the best he’s been driving so far," added Lowe.
"That’s a tough prospect for any driver to compete with."
Hamilton, who worked with Lowe at McLaren before both moved to Mercedes, arrived in Spain with a cavernous 27-point lead over Rosberg.
He has started every race on pole and was fastest in Friday's second practice at the Circuit de Catalunya.
Rosberg was boosted by a strong showing in Bahrain three weeks ago, however, with Mercedes boss Toto Wolff hailing an 'exceptional' performance and declaring the German back to his best.
Lowe agreed Rosberg had performed well at Sakhir, and had been let down by the team in the closing stages.
"You saw he did some fantastic driving, some great overtaking," he said. "I think Nico is doing a good job, it's just tough to beat Lewis."
Whether he can halt Hamilton's run of success on Sunday remains to be seen.
The champion won in Spain from pole position last year, a season in which Rosberg pushed him all the way to the end despite winning only five times to Hamilton's 11, and sounded unconcerned.
"If he is saying he brought his best game last year then I don't really have too much to worry about," Hamilton told reporters.
(Editing by Amlan Chakraborty)