Alonso posted the quickest lap in his Ferrari on a chilly, damp day of practice at the Canadian Grand Prix on Friday, although he wasn't going to get excited about being fastest in the 22-car field in a mere practice.
Especially since his lap time held up mainly because a sprinkle of rain slowed cars through the final 15 minutes of the 90-minute afternoon session, just when most drivers are ready to make their fastest laps.
"It depends on which moment you do your lap and the conditions on the circuit whether you are quickest or not," Alonso said. "The most important thing was to evaluate some new parts we brought here, and the new tires that Pirelli brought as well. Some of it we managed to do."
Alonso navigated the 4,361-kilometre Circuit Gilles Villeneuve, which is slick even when it doesn't rain, in one minute 14.818 seconds, just ahead of defending Canadian Grand Prix winner Lewis Hamilton's Mercedes in 1:14.830.
Romain Grosjean, who finished second here last year, was third-quickest for Lotus followed by Mark Webber's Red Bull, Nico Rosberg's Mercedes and Felipe Massa in a Ferrari.
Alonso won world championships in 2005 and 2006 for Renault, but the 31-year-old was unable to catch Sebastian Vettel's Red Bull as the German won championships the last three years.
But he is making a case with two wins in the opening six races this season, the same as Vettel, who leads driver standings with 107 points. Lotus veteran Kimi Raikkonen is second with 86 and Alonso third with 78.
When asked who he expected to be his chief competition this weekend, Vettel didn't overlook Ferrari.
"On one lap, if you look at the time sheet, the Mercedes again looked very quick," he said. "The Ferrari looked competitive in both long and short runs.
"So I think those will be the main rivals. But never forget the Lotus. They could be a surprise in the race."
There is one more practice session on the schedule before qualifying on Saturday afternoon, when more damp weather is forecast. The sun is expected to appear for the race on Sunday.
It complicates all the teams' experiments with tires, car set-ups and other factors ahead of the race on what is considered one of the more difficult tracks in Formula One.
Circuit Gilles Villeneuve is known for being tough on brakes and tires with its long straightaways leading into tight corners and chicanes. The asphalt is slippery because it is only used once a year for racing. Any grip-enhancing rubber laid down in practice may be washed away by rain.
It was not ideal for tire supplier Pirelli either. The Italian firm brought its new, more durable tires for use in practice for the first time, but due to the conditions teams could only use them for about five laps.
The new tires, reinforced with Kevlar rather than steel to reduce degradation, were supposed to go into full use at the British Grand Prix in two weeks, but that may now be delayed.
"We did what we could," said Vettel. "It was a bit tricky to test different things because it was so slippery, but it was the same for everybody."
Rosberg, coming off a victory at the Monaco Grand Prix two weeks ago, will be gunning for a fourth straight pole position.
Hamilton is looking for a fourth Canadian Grand Prix victory. The Briton posted his first F1 win in Montreal in 2007, and also won in 2010 and last year.
But they were all for the McLaren team, and he now races for Mercedes.
Vettel, meanwhile, has never finished better than second at Circuit Gilles Villeneuve.
"No extra pressure because of that," Vettel said. "I like coming here despite the fact we haven't won.
"Today was a good day, but slippery. (Saturday) the weather is again going to be a factor. Then we'll see on Sunday."
With Hamilton gone, the McLarens have slipped on the grid, leaving their top driver Jenson Button 10th in drivers standings with only one top-5 finish this year.
Button won the Canadian race in 2011, and hopes the unpredictable conditions will help him this week, even if he is not even thinking about winning.
"We all think we have a chance of winning in different conditions, but the reality is that it's going to be very difficult for us," he said. "That's why we go racing, but we know realistically it's not going to happen.
"So our aim is to get some good points in. I'm not hoping for a certain position. I just hope we make improvements and get closer to the front."
Times in the afternoon session were about seven seconds faster than in the morning, when Paul Di Resta of the Force India team led at 1:21.020.
The late rain led to some slipping and sliding, including a near-crash between Webber and Grosjean. Kimi Raikkonen's Lotus also went for a slide.
Pastor Maldonado hit a wall late in the morning session and damaged the front wing on his Williams, while Jules Bianchi's Marussia stopped on a slip road after 41 minutes, ending his session. Several others, including Button and Hamilton, had minor slides but kept going.
"It's been a fun day of weather," said Button, who was ninth-fastest. "We've had dry, wet, in the middle.
"It's a pity at the end that we had a gearbox issue, so I didn't get a long run, which would have been quite useful, especially around here. But there's still a lot of data to go through."