Willian: We can still qualify for the Champions League quarter-finals. Photo: Will Oliver/EPA

LONDON – Chelsea goalscorer Willian said they must go on the attack against Barcelona at the Nou Camp next month to have any chance of reaching the Champions League quarter-finals.

The Brazilian’s fine goal was not enough for victory in a compelling last 16, first leg at Stamford Bridge as Lionel Messi pounced after a defensive mistake by Chelsea to earn Barca a 1-1 draw which has left the fascinating tie evenly poised.

“It is still open and we have showed we can compete and we will need another excellent performance at the Nou Camp to go through,” said Willian, who hit the woodwork twice in the first half. “You have to have a lot of personality to play against this team which has 70 percent of the ball. We have to go there to attack and score because 90 minutes defending at the Nou Camp is an eternity, it is a suicide mission.

“We have to play our game.”

Chelsea have knocked Barcelona out twice in the knockout stages - most recently in the semi-final in 2012 when they won 1-0 at home before drawing 2-2 in Spain.

A similar result in the return leg would put them through and Eden Hazard said they must be positive.

“At least we won’t be able to think defensively about the second leg because if we think defensively over there we would be in a lot of danger,” Hazard said. “We will go there trying to win because we have to score and we will try to pull off the perfect game as we did today except for the small mistake that we made,” added the Belgian. “It’s not over. We can still dream. Qualification is still possible.”

But for Andreas Christensen’s rash pass across his area in the 75th minute, ruthlessly punished by Messi, Chelsea would have taken a slender lead into the second leg.

Manager Antonio Conte defended the 21-year-old Dane though.

“Christensen’s performance was a great performance. An incredible performance,” Conte told reporters. “He’s only 21. It’s great that he’s able to play this game with this maturity, this personality. I repeat: Christensen for me, he was one of the best players tonight.

“It’s very difficult to tell one or another player, but I think Christensen played a top game.”

Barca striker Luis Suarez, kept quiet for most of the night, said that moment could prove crucial.

“The goal will give us a huge advantage in the second leg and allow us to have more space in the Nou Camp,” he said. “Our virtue is that we are stronger at home. That’s why it was so important to score today. Now they are obliged to go looking for a goal at the Nou Camp and we’ll have more space.”

Meanwhile Messi had to wait 12 years and endure a goal drought of eight games against Chelsea but he finally broke his duck on Tuesday.

The last time Barca played Chelsea, in a semi-final in 2012, Messi whacked a penalty against the bar which allowed the London side to claw their way back to an unlikely win at the Nou Camp.

The diminutive Argentine atoned on Tuesday, giving Barcelona a precious away goal as he strode on to a pass from Andres Iniesta and calmly side-footed the ball home to cancel out Willian’s opener for Chelsea.

“For us he is the best player in the world. He’s not just any player,” Barca midfielder Ivan Rakitic said of Messi, who has now scored 98 Champions League goals compared to his Real Madrid rival Ronaldo’s 116 in the competition.

“We have a lot of faith in him. We know that what we need to do is free him up as much as possible. And it’s not easy for him, he gets so little space, it’s hard for him.”

Tuesday’s Champions League encounter was the ninth time that Messi had faced Chelsea, a run of games stretching back to 2006 when the sides met in the competition’s group stages. That kicked off a series of often epic encounters between the teams in the following six years.

Yet even during the 2011/12 season, when Messi scored 73 goals for Barcelona, he failed to find the net in the two games he played against the Blues.