Hamilton knows size of task
Lewis Hamilton believes he faces "a steep uphill climb" if he is to become a double Formula One world champion this season.
After four grands prix of an unpredictable year to date in which there have been four different winners, Hamilton is still waiting for his first victory.
A trio of third-place finishes in Australia, Malaysia and China initially gave him the lead of the championship for a week until he was deposed following a disappointing eighth in Bahrain last time out.
That was as a result of issues in the first two of his three pit stops, leaving him languishing behind Sebastian Vettel, with the reigning champion taking over at the top of the standings.
Initial optimism within McLaren, in particular following Jenson Button's triumph in Australia, has since been tempered.
There is now the realisation with the title race more wide open than has been the case for many a year, winning it is arguably going to be more difficult than ever before.
Asked as to his chances, even though there are 16 races to run and in trailing Vettel by four points ahead of Sunday's Spanish Grand Prix, Hamilton said: "It's going to be very tough.
"It's going to be a steep uphill climb, but then everyone is in the same boat. It's about consistency. That's the most important thing."
It is that consistency that eluded Hamilton in practice today, even though he finished fourth quickest at Barcelona's Circuit de Catalunya at the end of the two 90-minute sessions, half a second down on Button.
Far from happy, Hamilton said: "It's not been a great day as I've struggled with set-up.
"I'm just not really sure on things because we had a bit of an inconsistent set-up, which means it's very difficult to pinpoint exactly what I need to do to change it to make it better.
"I'll look at the data to see where the most serious issues are and try and correct it for tomorrow."
At least Hamilton was happy with the upgrades on the McLaren, which for this weekend includes a new, slightly-raised nose.
"The upgrades worked well and I've great pace generally, in particularly on the longer runs so at least we're in the fight," added Hamilton.
"The car already feels better than it did in the last race, but we're still trying to work on managing the tyres.
"My last run, though, was pretty spectacular for me. I've never had tyres last that long and I could have kept going if we hadn't run out of time.
"So there are positives, but there is a lot more time for me to get out of the car, as we saw with Jenson's fantastic lap."
You would have thought Button would be happy enough, but that was far from the case as he again bemoaned his struggles with tyres.
For this race Pirelli are using the hard and soft compounds, and whilst Button was content with the latter, posting a lap time of one minute 23.399secs, the latter had him shaking his head.
"It was a good afternoon, but a tough afternoon because I'm still trying to understand the tyres," said Button.
"The car seems to be working on the soft tyre, but on the hard I can't get it working. I can't get the temperature into them, and I don't know why that is.
"On the first run (on the hard tyre) I did three laps and I just couldn't get the fronts working.
"We came in, changed something to make them work, and I went five to six tenths (of a second quicker) straight away. That's unheard of for the tyres this year.
"The car felt transformed, so we are able to make the tyre work, it's just that they jump out of the window quite easily.
"It's something we need to sort out because when it works, it works well, and when it doesn't it's obviously dreadful so we have to try and get it in the right area."
Vettel was second quickest, followed by Mercedes' Nico Rosberg. However, Button feels it is Lotus duo Kimi Raikkonen and Romain Grosjean, fifth and sixth on the timesheet, who appear strong.