Katie Boulter thrashed Germany’s No.1 Laura Siegemund to see Great Britain race into the quarter-finals of the Billie Jean King Cup – and announce themselves as potential winners of the title.

Emma Raducanu got her team off to a winning start by beating Jule Niemeier 6-4, 6-4.

And British No.1 Boulter brought her recent hot form in Asia to the Costa del Sol to send Siegemund home after a 6-1 6-2 defeat in only 70 minutes. There was no need to play the doubles.

Anne Keothavong’s team will now face defending champions Canada on Sunday for the chance to reach the semi-finals.

And the only two top 10 players in the event – Poland’s Iga Swiatek and Jasmine Paolini of Italy – are on the other side of the draw.

Boulter was broken in the opening game but then won the next six games as world No.84 Siegemund failed to win any of her eight points on her second serve in the first set. She only won one point in the second set and made 29 unforced errors.

And the Leicester City fan took her second match point with an inside-out forehand winner to see GB reach the last eight without dropping a set.

Boulter, who reached the final of the Hong Kong Open in her last tournament, said: “Obviously I am thrilled in getting a rubber for Great Britain.

“Matches like this mean so much more with the flag on the chest. Emma played great to get the first win and I came out and had a free swing.”

Like Raducanu earlier, Boulter paid tribute to the British fans in the Palacio de Deportes. “Honestly, it feels like we are in Great Britain right now,” said the world No.24. “Our fans are outstanding.”

Keothavong added: “I am a very proud captain. It was a fantastic performance from Emma and Katie. Emma having been off for a period of time, the way she dealt with it was a good performance.

“And the way Katie started and got the job done. I couldn’t be more proud of both of them and the whole team. We know we have Canada next. We are going for the win.”