Kyle Edmund stepped up in Andy Murray's absence to give Great Britain the perfect start against Kazakhstan in a decisive Davis Cup group tie in Madrid.

Assured of a quarter-final place with a victory, Britain lead 1-0 in the three-rubber tie after Edmund won 6-3 6-3 against Mikhail Kukushkin.

British number one Dan Evans will put his team in the last eight if he beats Alexander Bublik later on Thursday.

Murray has been rested as he continues his comeback from hip surgery.

If Evans loses, Britain will have another chance to win the tie through Jamie Murray and Neal Skupski in a deciding doubles rubber which follows the second singles match.

Kazakhstan, backed by a rowdy set of supporters, need to fight back to win or they will be eliminated from the new-look 18-team finals tournament which is being played across the week in the Spanish capital.

Britain could still reach the last eight as one of the two best runners-up even if they are beaten by the Kazakhs, although it would only be a slim chance with Group B runners-up Russia already guaranteed to qualify ahead of them.

Edmund rediscovers form to give GB advantage

Murray's absence was unsurprising after the Scot laboured to a three-set win over Dutch world number 179 Tallon Griekspoor on Wednesday, which left him admitting he was not as sharp as he would like to be after taking a month off competitive tennis to spend with his new-born son and family.

That placed the pressure on 24-year-old Edmund to perform, at the end of a year in which he struggled for wins and tumbled down the world rankings as a result.

But Edmund, the 2018 Australian Open semi-finalist who has dropped to 69th in the world, outplayed 67th-ranked Kukushkin in a noisy Caja Magica.

Kukushkin was backed about 100 boisterous and colourful fans, armed with drums and a trombone like they were when their women's team played Britain in the Fed Cup earlier this year.

However, that did not put off Edmund, who himself was well supported by a noisy contingent of Union Jack-waving British supporters, who have travelled to Madrid in their droves.

Edmund showed no signs of the troubles which have plagued him on the ATP Tour this year, hitting 10 aces and 23 winners in a dominant performance.

The Yorkshireman's explosive forehand - his key weapon - was particularly destructive, helping him take his fourth chance in the decisive break of the first set and save two break points in the following game.

After breaking again for a 4-2 lead in the second set, he took eight of the last nine points to race through the closing stages, converting his first match point when Kukushkin hit a forehand long.

That meant Edmund won in just one hour and 15 minutes, leaving the celebrating British fans dancing in the stands, while finally silencing the Kazakhs.

"The atmosphere has been amazing, I think we have got the most travelling fans so amazing to get so many people coming here from Britain," Edmund said.

"I couldn't wait to get out here and it was such a buzz to thrive off the crowd."

How Britain's qualification hopes could pan out

Barcelona footballer Gerard Pique has overseen the transformation of the 119-year-old competition into a season-ending finals, which sees the 18 nations split into six groups of three.

The six group winners automatically qualify for the quarter-finals with the two best-placed runners-up joining them.

Britain's 2-1 win over the Netherlands in their opening group match on Wednesday means they will top Group E by beating Kazahkstan.