South African fly-half Morne Steyn kicked all of Stade Francais' points in a 19-15 defeat to three-time European champions Toulon who snatched victory with a last-gasp try in a tense French Top 14 duel on Sunday.

Stade remain second from bottom of the table while Toulon are sixth, five points behind leaders Montpellier after five games.

Toulon owed their win to Argentine back-row forward Facundo Isa who barrelled over after sustained pressure with veteran All Black star Luke McAlister kicking the conversion for good measure with two minutes left on the clock.

Stade's backs coach Julien Dupuy blasted a series of decisions by referee Jonathan Dufort which he described as "a scandal" which "drives me crazy".

Dupuy said rulings which worked against his struggling team included a "non-existent" knock-on by Remy Bonfils in the build-up to Toulon's winning try while he also claimed Stade should have been awarded a penalty try when Josua Tuisova impeded Sergio Parisse on the try-line in the 43rd minute.

Fijian winger Tuisova made the most of his reprieve by adding a 60th-minute try to his first-half opener.

It was a first away win of the season for Fabien Galthie's team after two defeats, the most recent of which was a 43-20 humbling at the hands of Montpellier.

Defeat was tough on Steyn who had landed a monster 40-metre drop goal with 10 minutes left to give Stade a 15-12 edge before Toulon battled back.

"It's not easy to win here," said Galthie. "It's a great moment. And for Stade Francais? I am not worried about them."

Earlier Sunday, New Zealander winger Toby Arnold was among the scorers in Lyon's comprehensive four-try 31-12 win over Castres.

Arnold crossed first for Lyon with the former All Blacks Sevens international followed by Mickael Ivaldi, Alexis Palisson and Baptiste Couilloud.

Lionel Beauxis converted all four and added a drop goal to put Lyon, who also had two tries disallowed, in control early in the second half.

Castres' points were kicked by South African Rory Kockott and Yohan Le Bourhis.

Defeat left the visitors, who had Jodi Jenneker's try disallowed, in 10th.

"How can we win a game against a team so full of confidence and scoring tries so easily?" asked Castres coach Christophe Urios.

"Today, despite tricky conditions and not a great second half, we came away with a bonus win," said Lyon skipper Julien Puricelli.

His coach Pierre Mignoni added: "By experience I know that wins create confidence, but even so I don't want the players to have their heads in the clouds."

The bonus-point win lifted Lyon up to third, level on 18 points with second-placed La Rochelle, with Montpellier, beaten by Bordeaux-Begles on Saturday, a point in front.

All Blacks star Aaron Cruden had two tries disallowed as his Montpellier team suffered their first defeat of the season on Saturday, going down 47-17 at Bordeaux.

La Rochelle claimed a third successive win with a 57-12 mauling of promoted Oyonnax.

Source: AFP