Suninen unhurt after crash as patchy ice tests drivers to the limit on Thursday.
Ott Tänak won this afternoon's opening two speed tests to claim the early lead at Rallye Monte-Carlo.
The Estonian crashed heavily in the FIA World Rally Championship's season-opener 12 months ago, but there were no mistakes today as he ended the short opening leg with a 3.3sec advantage over Kalle Rovanperä.
Tänak, driving a Hyundai i20, won the 20.58km special stage from Saint-Disdier to Corps by 3.0sec from the Finnish youngster. He added a further three tenths to his lead by taking the following 20.78km test from Saint-Maurice to Saint-Bonnet, despite stalling at the start.
Conditions in the opening test were wet but patchy ice early in the next stage made grip unpredictable. Nevertheless, Tänak, like virtually all the leading crews, opted for Pirelli's supersoft compound asphalt tyres.
"It was looking like quite a simple start to the Monte, normally we've never started in daylight and in these consistent conditions. In the end the first one wasn't so bad but the second one, with a lot of cuts and muddy places, was demanding with a lot of surprises," he explained.
Rovanperä enjoyed a trouble-free run in his Toyota Yaris to end the day 5.2sec clear of team-mate Elfyn Evans. The Welshman was almost caught out on a slippery right corner in SS1 and struggled to generate heat in his tyres in the early part of SS2.
Thierry Neuville was fourth in another i20, 16.0sec off his team-mate's pace. The Belgian was co-driven by Martijn Wydaeghe for the first time after splitting with long-term partner Nicolas Gilsoul last week. The pair settled in well, despite sound problems in the intercom.
Sébastien Ogier started his title defence in fifth, less than a second adrift of Neuville. The Frenchman had intermittent brake problems in his Yaris but had almost half a minute in hand over Dani Sordo, who was unnerved by a strange noise in his i20.
Pierre-Louis Loubet was seventh in a similar car, 25.1sec adrift of the Spaniard, with WRC2 leader Andreas Mikkelsen next up in a Skoda Fabia. Fellow support class contender Adrien Fourmaux was ninth with a frustrated Gus Greensmith tenth in his Ford Fiesta.
Takamoto Katsuta was just off the leaderboard after spinning his Yaris in both stages.
Teemu Suninen was the first retirement. The Finn set a storming pace through the opening test and was on course for fastest time before running wide into a bank, rolling back across the road and plunging down an embankment.
Friday hosts the 'meat' of the rally with almost 105km of competition across five stages west of Gap. Two loops of two tests sandwich a single pass through the longest stage of the weekend. The action kicks off before dawn at 06.10, with service after the first three tests.
Leading positions after Thursday
1. O Tänak / M Järveoja EST Hyundai i20 24m17.5s
2. K Rovanperä / J Halttunen FIN Toyota Yaris +3.3s
3. E Evans / S Martin GBR Toyota Yaris +8.5s
4. T Neuville / M Wydaeghe BEL Hyundai i20 +16.0s
5. S Ogier / J Ingrassia FRA Toyota Yaris +16.9s
Elfyn Evans (GB) and Scott Martin (GB) of team Toyota Gazoo Racing are seen racing on special stage nr. 1 during the World Rally Championship Monte Carlo in Gap, France on 21,January