Although the British team and Japanese engine manufacturer have shown steady improvements since last year’s annus horribilis, Alonso and team-mate Jenson Button have yet to become regular points-scorers, let alone return to winning ways.
“We need to be more or less happy, proud of the progress the team has made in the last 12 months, but we have to keep our feet on the ground,” the Spaniard is quoted as telling Sky Sports by GPUpdate.net.
“We know that being champions will require a lot more – there's still a long way to go.
“I’m remaining positive and optimistic for next year, because the direction [we are heading] is definitely a good one, but we need to accelerate somehow this process.”
Alonso, who is turning 35 this summer, recently said he did not intend to linger in Formula One and knows the clock is ticking for him to secure a third world title.
With only one year left on his McLaren contract beyond 2016, the former Ferrari star urges his team to further cut the substantial engine deficit that still exists with the front-running outfits over the second half of the current season.
“We're still some horsepower behind the competition,” the 2005 and ’06 champion added.
“We need to see some progress on that, because the gap is quite big right now.
“We need to close that gap and then in the winter hope that the gap will disappear. I think that if we keep this gap for the whole season, it will be too big to do it only in the winter.
“That's the main hope for the rest of the season… some updates from the engine, some tokens that we may use and get a little bit closer to the Mercedes, which is the dominant power unit.”