Worcester Warriors and ASM Clermont Auvergne clinched quarter-final places in the European Rugby Challenge Cup with a round to spare after thrilling victories on Saturday.

A 79th minute drop-goal from Ryan Mills sealed a 20-18 win for Worcester at Ospreys and top spot in Pool 2 ahead of the Welsh region, as even if the teams finish level on 17 points, the English club are ahead of Ospreys on the head-to-heads 8-2 in match points.

Tries from Jonny Arr, Ollie Lawrence and Dean Hammond ensured Worcester ended their 10-year run of failing to make the knockout stages of the tournament.

It has been rather more comfortable for Clermont, who made it five bonus-point victories from five Pool 1 games with a sensational 48-40 home success against Northampton Saints.

The two-time Challenge Cup winners, who also lead the TOP 14, edged the 13-try spectacular 7-6, with Peter Betham and Wesley Fofana grabbing doubles, while Teimana Harrison notched a hat-trick for Saints.

The three other pools will go right to the wire, although La Rochelle are strong favourites to head Pool 4, as they lead that group by four points from Bristol Bears after their 32-12 home win over Zebre Rugby Club on Friday and Bristol’s 65-9 victory at Enisei-STM on Saturday.

Harlequins and Benetton Rugby have pulled clear at the top of Pool 5, but only a point separates leaders Harlequins from the Italian side after both scored comfortable home wins in Round 5.

Quins overcame Grenoble 38-20 at The Twickenham Stoop, while Benetton defeated Agen 38-24 helped by a try treble from Tito Tebaldi. Both now face away games in France on Friday night – Quins at Agen and Benetton at Grenoble.

The tightest group of all, though, is Pool 3, where Sale Sharks are ahead of Connacht Rugby on points difference only after Connacht’s dramatic 20-18 home triumph over the English club on Saturday.

The Irish province needed a 71st minute penalty from David Horwitz to end a superb Sale fightback inspired by Faf de Klerk, who scored 13 points, after Connacht had opened up a 17-0 lead.

Next Saturday Connacht travel to Bordeaux-Begles, while Sale entertain Perpignan.