The Watford manager is enjoying the football Blues are now producing.
“The way Chelsea are playing in the League is quite impressive,” Zola told the London Evening Standard.
“They have become quite an offensive team, something Chelsea have never been, and it’s nice to watch. It’s a massive test because their forward play will be tested by the hardest team to beat in the League. If they come through it, people will have to take them seriously in the title race and I believe they can win.”