Brad Thorn's first try in Leicester colours and 20 points from Owen Williams gave Tigers a famous 25-21 victory over defending European champions Toulon at Welford Road on Sunday.

Tigers raced into a 13-0 lead in the European Rugby Champions Cup Pool 3 clash through Thorn's close-range finish, which was converted by Williams.

They had to weather a fightback from Toulon, the French Top 14 champions and current league leaders, who went in level at 13-13 at half-time through Bryan Habana's intercept try.

Toulon took the lead for the first time in the contest through Drew Mitchell's try in the second half. But Tigers held firm and Williams held his nerve in the tensest of atmospheres to knock over three penalties and give Tigers a second win from their three European fixtures.

Ben Youngs returned from international duty with England to captain Tigers, Matt Smith came in at centre with Vereniki Goneva switching to the wing.

The only change n the pack saw the return of Jordan Crane at No8, while Geoff Parling was included among the replacements following recovery from injury.

For Toulon, Martin Castrogiovanni made his first return to Welford Road since his move to Toulon in 2013.

The game started at a frenetic pace with Tigers putting their visitors under plenty of early pressure in front of 22,114 spectators. The figure took Tigers past the one million mark for home attendances in European competition, and what a contest they witnessed.

Owen Williams caught Toulon napping by running a penalty from his own half but Matt Smith spilled possession. A loose pass was swooped on by Anthony Allen but his pass from the floor was intercepted by a retreating Nicolas Sanchez.

Williams was at the centre of the early action, charging down a clearance to keep the pressure on Toulon before knocking over a penalty, won by the Tigers scrum, to give Leicester a 3-0 lead after nine minutes.

Toulon turned down a long-range penalty to go for territory after Tigers were pinged at a breakdown but Guilhem Guirado's throw was not straight and the chance was lost.

Castrogiovanni was whistled for charging into a ruck after referee Nigel Owens had blown his whistle, and Williams doubled Tigers' lead with the penalty.

Tigers continued to put Toulon under massive pressure, forcing the French league leaders into uncharacteristic mistakes. And it was from a fumble by Australia international Drew Mitchell that they scored the first try. Mitchell, heading back towards his own line, was unable to gather a loose pass, Tom Youngs grabbed the ball and found Thorn in support, who crashed over from close range.

Williams' conversion gave Tigers a 13-0 lead midway through the first half.

A scrum penalty awarded on the Leicester 22 gave Toulon their first effort at goal after 22 minutes and Sanchez, the Argentina fly-half, cut Leicester's lead to 13-3 with his kick.

Williams' loose pass on halfway was hacked into the Leicester 22 by Steffon Armitage. Ben Youngs scampered back to gather the ball in front of his line, Williams then flung the ball wide to Goneva who attempted to launch a counterattack but was forced into touch.

Toulon were awarded a penalty as Tigers infringed at the lineout drive but Sanchez was off target with his touchline kick.

A handling error on the Tigers 22 had Leicester under pressure as Toulon flooded forward. Tigers regrouped and held off drives from Castrogiovanni and Bakkies Botha before the home side conceded a penalty on their line. Sanchez landed his kick to cut the lead to 13-6.

Williams was wide with a kick from the right touchline after Steffon Armitage had failed to release Tom Youngs in the tackle.

Instead, Toulon drew level in the blink of an eye. Williams' pass in midfield was intercepted by Bryan Habana, who had a free run to the line from halfway. Sanchez's conversion levelled matters at 13-13 five minutes before the break.

There were no changes for either side at the break.

The Tigers pack got a huge shove on the Toulon eight at the first scrum of the second half and Williams made no mistake to kick the hosts into a three-point lead.

Tigers had to be alert to a clever lineout move on their 22, Guirado picking out centre Maxime Mermoz off the back. The defence held firm and Tigers were awarded a scrum put-in for a forward pass.

However, Toulon stole possession at the scrum. Sebastien Tillous-Borde darted down the blindside where Mitchell provided the overlap to dive over at the corner. The try was unconverted but gave Toulon the lead for the first time in the game.

Back came Tigers, putting together a series of phases to take them into the Toulon 22. There Toulon were pinged for not releasing and Williams had a simple penalty to give Tigers a 19-18 lead after 57 minutes.

A clever Ben Youngs box kick had Toulon under pressure on their own throw five metres from their line. Tigers made a mess of the lineout, forcing Toulon into touch to earn their own lineout. They set up the drive and had Toulon back-pedalling but the maul was forced into touch in-goal.

Ben Youngs then darted down the side of a ruck to take Tigers back into the Toulon 22. There he won a penalty for being held in the tackle and Williams landed his kick to move Tigers 22-18 ahead with 15 minutes remaining.

Toulon responded with a series of phases on the Leicester 22 where the home defence were ruled to have gone offside and Sanchez had a simple penalty to cut the lead to 22-21.

Jamie Gibson stole Toulon lineout ball on their line to give Tigers an attacking platform. However, Robert Barbieri, the replacement back rower, knocked on as he tried to drive home the position.

With such a fine margin between the teams the tension aroubnd Welford Road was tangible. It seemed to affect Goneva when he attempted a drop goal from 30m on the angle and miscued it dead.

Tigers were awarded a penalty on halfway with two minutes left after Youngs was taken out at te back of a ruck by Habana. And Williams made him pay with a monster kick that just had the legs to clear the crossbar for the final points of a thrilling and absorbing game.