Ulster outscored Clermont five tries to four in a fascinating contest at the Kingspan Stadium, eventually winning 39-32.
The first half of the match was a fantastic advert for European rugby. Peceli Yato got the scoring underway for Clermont after just 69 seconds with Scott Spedding also scoring in the opening half for the visitors.
However, Luke Marshall, Iain Henderson and Paddy Jackson scored tries sent Ulster into the break with the lead.
The second half was equally exhilarating, as Marshall completed his brace early in the half before Chales Piatau looked to have killed the game off with a fifth try.
Despite a 21-point deficit, Clermont rallied and tries from Nick Abendanon and Damien Chouly gave Ulster a scare, but they held out to secure a stunning bonus-point victory.
For their late surge, the French side leave Belfast with two bonus points, meaning they lead Ulster by three points atop Pool 5.
With just over a minute on the clock, Clermont scored the first try of the match, Fijian back-row Yato scoring under the posts for the visitors to get the scoreboard ticking.
Morgan Parra added the extras to establish an early seven-point lead. Ulster hit back with a try of their own after seven minutes. Marshall powered straight through the Clermont defence to score at the posts. Jackson converted the score to draw the sides level.
A penalty from Parra after ten minutes nudged the French side back into the lead after Ulster were penalised for not rolling away.
The exhilarating start to the match continued after 16 minutes. Ruan Pienaar’’s cross-field kick was expertly brought down by Tommy Bowe who off-loaded to Henderson to score a great try. Pienaar missed his conversion but his side had claimed a 12-10 lead.
Jackson kicked a penalty after 22 minutes before Parra responded with another penalty five minutes later. This took the score to 15-13.
Spedding scored the game’’s fourth try after 31 minutes – a pick and go bringing the ball forward for the 2015 finalists before Camille Lopez and Rémi Lamerat skilfully moved the ball out wide for the full-back to cross in the corner and nudge the visitors in front at 15-18.
A brilliant individual effort from Jackson created the game’’s fifth try, adding the extras himself to nudge the home side back into the lead by four points heading into the half-time break.
Marshall scored his second and Ulster’’s fourth try of the match in the 45th minute to secure a bonus point; a lofted pass from Pienaar set up the try for Marshall after a huge carry from Stuart McCloskey. Jackson converted successfully to extend his side’s lead to 11 points.
The hosts made it five after 54 minutes, Piatau beating three men brilliantly before scoring in the right-hand corner.
Jackson’’s fine goal-kicking form continued in the 58th minute as he kicked a penalty for the home side from 50 metres, sending them into a convincing 21-point lead.
Clermont’’s third try came after 63 minutes, Abendanon scoring under the posts to keep the match alive for the French side.
A fourth try for the French side arrived with just six minutes left on the clock. Chouly powered over at the posts before Parra converted to make the score 39-32.
Despite the late surge, the Top 14 leaders came up short in their pursuit of a draw, in spite of Rodney Ah You’’s late sin-binning for the hosts.
Tries: L Marshall 2, Henderson, Jackson, Piutau
Cons: Jackson 4
Pens: Jackson 2
Yellow Card: Ah You
Tries: Yato, Spedding, Abendanon, Chouly
Cons: Parra 3
Pens: Parra 2
Ulster: 15 Charles Piutau, 14 Tommy Bowe, 13 Luke Marshall, 12 Stuart McCloskey, 11 Louis Ludik, 10 Paddy Jackson, 9 Ruan Pienaar, 8 Sean Reidy, 7 Chris Henry, 6 Iain Henderson, 5 Robbie Diack, 4 Peter Browne, 3 Wiehahn Herbst, 2 Rory Best (c), 1 Kyle McCall
Replacements: 16 Rob Herring, 17 Andy Warwick, 18 Rodney Ah You, 19 Kieran Treadwell, 20 Clive Ross, 21 Paul Marshall, 22 Darren Cave, 23 Jacob Stockdale
Clermont: 15 Scott Spedding, 14 David Strettle, 13 Rémi Lamerat, 12 Wesley Fofana, 11 Nick Abendanon, 10 Camille Lopez, 9 Morgan Parra, 8 Peceli Yato, 7 Alexandre Lapandry, 6 Damien Chouly (c), 5 Sébastien Vahaamahina, 4 Flip van der Merwe, 3 Davit Zirakashvili, 2 Benjamin Kayser, 1 Raphaël Chaume
Replacements: 16 Yohan Beheregaray, 17 Etienne Falgoux, 18 Clément Ric, 19 Sitaleki Timani, 20 Camille Gerondeau, 21 Ludovic Radosavljevic, 22 Benson Stanley, 23 Alivereti Raka
Referee: Wayne Barnes (England)
Assistant Referees: Peter Allan (England), Paul Dix (England)
TMO: Sean Davey (England)