Johanna Konta made an excellent first impression for prospective coach Dimitri Zavialoff by defeating Elise Mertens in the opening round of the Kremlin Cup in Moscow.

The British number one split from Michael Joyce last week after a disappointing first season together and is working with Frenchman Zavialoff, long-time coach of Stan Wawrinka, on a trial basis at her final tournament of the season.

Konta has looked low on confidence for much of 2018, with her ranking tumbling to 44, but this performance was reminiscent of the top-10 player she was for the past two seasons as she saw off seventh seed Mertens 6-3 7-5.

The victory was only Konta’s fifth over a top-20 opponent all season and was all the more impressive given the high-quality nature of the contest.

The British number one was particularly effective on Mertens’ second serve, winning 20 of 29 points overall and breaking the Belgian, who hit nine aces, four times.

Konta only faced two break points herself and one of the most encouraging aspects of the match was the way she withstood pressure after getting an early break in the opening set and then again in the second.

Mertens’ only success on Konta’s serve came in the opening game of the second set but the British player recovered the break to make it 4-4 and then broke again in the final game.

She will face either Australian Daria Gavrilova or lucky loser Vitalia Diatchenko in the second round.