Jenson Button believes McLaren’s start to the 2018 Formula 1 world championship could be considered “a disappointment” after setting high targets having felt it has one of the best cars on the grid.

The 2009 F1 world champion ended his long-term affiliation with McLaren last year having retired from the sport during the team’s frustrating partnership with Honda.

Despite struggling with underpowered and unreliable Honda engines, McLaren frequently pointed to the strengths of his aerodynamic package and chassis as one of the best on the grid.

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After switching to Renault engines for this season McLaren has appeared to be down on pace compared to fellow Renault-powered teams, the factory team and Red Bull, and the pace drop has led to the Woking-based team assessing its own technical squad and downplaying targets. Button feels the issues around McLaren's predicted performance is from its belief in 2017 that its car could compete with the top teams if it had an equal engine.

“With the three big teams, it's difficult to challenge them at the moment and it's going to take a while,” Button told Sky Sports.

“McLaren came out last year and this year and said they think they might have the best car. It's a tall order to have the best car in Formula 1 when you're racing against Ferrari and Mercedes and Red Bull. And I think we've seen that isn't the case.

“So you'd say the season so far is a disappointment but if they didn't say they had the best car you'd say it's a great season for them.”

Despite playing down its progress, Button is confident his former team will continue to make strides in performance over the season but feels McLaren may have to shift expectations.

“They've made good steps, they're fourth in the constructors' standings,” he said. “But because of what they said at the start of the year you say maybe it's not what we expected.”

McLaren currently holds fourth place in the F1 world constructors’ championship by a single point from Renault, behind the top three teams of Ferrari, Mercedes and Red Bull, while in the drivers’ standings Fernando Alonso heads up the midfield fighters in sixth place.

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