A day of disruption means Jenson Button is unable to predict a change in fortunes for McLaren at this weekend's Monaco Grand Prix.

The streets of Monte Carlo evoke so many good memories for the team, whose 15 successes here make them the most successful constructor in history.

McLaren's current line-up of Fernando Alonso and Button have both previously won in the principality, but getting anywhere close to repeating that feat looks highly improbable this time around.

The Woking-based team have endured their worst start to a Formula One season since entering the category in 1966 and approach the sixth race of the season looking to score their first point.

Issues with the new Honda power unit have made for a torrid start and Button fumed after the Spanish Grand Prix, saying "the first 30 laps were the scariest of my life".

His outlook has improved after a positive post-race test, although Thursday's practice sessions were frustrating due to disruptions caused by mechanical issues and then a downpour.

"You always want to run it here as much as you can," Button said.

"Monaco is very unique - a unique circuit these days, somewhere you need to build up.

"You can't just go straight out and go flat out, like most of the circuits these days. There are a lot of run-offs.

"You need a lot of laps - I didn't get a lot of laps, so Saturday morning is going to be very important, for me especially."

Asked if Thursday allows him to form an opinion on McLaren's capability in qualifying, the Brit said: "No, we haven't broken in the supersoft tyres. No one has, so it is impossible to say."

The importance of performing on Saturday cannot be underestimated in Monaco - nine of the past 10 races have been won from pole position.

Button goes as far as saying "Saturday is probably more important than Sunday" and is expecting an extremely busy day.

"P3 is going to be very busy because we didn't run any of the supersofts," the British driver said.

"It is going to be a busy morning with the set-up work. It will be an important morning and then we're into qualifying.

"There's no rest for the wicked but I am looking forward to it."

Button, like several other drivers, is a resident of Monaco and his vast experience should hold him in good stead on Saturday.

There have, though, been a few tweaks to the course this year and, despite only managing 29 laps during Thursday's practice sessions, does not appear to be a fan.

"I don't like Tabac as much," Button said. "It is just a bit tighter and it was nice and flowed well.

"The trouble is, I've been doing it for 15 years and suddenly it has changed. It is suddenly tighter and it catches you unaware at the moment.

"I think that's the problem (Mercedes driver) Nico (Rosberg) had and then the first part of the Swimming Pool seems a bit faster. I think they've tried to stop you drifting wide into the exit barrier on the left."