Katie Boulter put Great Britain 1-0 ahead in their Billie Jean King Cup play-off against Mexico with a straight-set win over Marcela Zacarias.

Heather Watson, the top-ranked player in the tie, faces Giuliana Olmos later on Friday, while Saturday features the reverse singles and a doubles rubber.

Victory would put Great Britain one win from qualifying for the 2022 Finals.

The Billie Jean King Cup is the new name for the Fed Cup, the women's international team event that Great Britain have finished runners-up in four times but have never won.

"Initially I was a little bit nervous," Boulter said. "Any match you play for Great Britain is a huge honour. I had the opportunity to do it today and I left it on the line and I got the job done and that is what matters."

Comfortable win & team-mate's tambourine

The atmosphere could not have been more different to Boulter's last Fed Cup appearance two years ago where she secured the winning point in a play-off against Kazakhstan at a packed and raucous Copper Box Arena in London.

Here it was her team-mates and the coaching staff who did their best to create some noise, with Katie Swan on her feet shaking a red a tambourine in between points.

Boulter made a slow start, losing her opening service game before breaking back in the fourth game.

She displayed her trademark grit to save two break points with some well-placed serves to go 6-5 up and sealed the set when Zacarias netted a backhand.

From then on the Briton did not look back, finding depth and speed on her shots to race through a 26-minute second set, claiming victory on her third match point with a powerful cross-court backhand winner.

"It was a really close first set and I managed to squeeze it through and that really helped me relax and so going into the second set I played some really good tennis," Boulter said.

"I've been playing some really good tennis in practice and I felt that when I settled I started to bring that out on the court."

Great Britain came into the tie as favourites with a couple of hundred ranking places between some of their players and Mexico's.

Boulter and Zacarias were, however, just six places apart in the rankings at 291 and 285 respectively, but the Briton was previously in the top 100 before a back injury sustained in the Fed Cup in 2019 sidelined her for a lengthy spell.

In the end it was Boulter's quality that shone through as she hit 19 winners to the Mexican's seven in what was ultimately a comfortable victory.