Spanish teenager Carlos Alcaraz dug deep to beat Russia's Karen Khachanov in testing conditions and reach the Madrid Open semi-finals.

In the women's singles, top seed Iga Swiatek continued her dominance on clay with a 6-0 6-3 win over Petra Martic.

Meanwhile, Britain's Andy Murray earned a much-needed clay-court win over Gael Monfils at an ATP Challenger event.

Alcaraz trying to 'play tennis differently'

Alcaraz announced himself to the wider sporting public at the same stage of the season last year, winning titles in Miami, Barcelona and Madrid to show exactly why those in tennis circles had long predicted he would become a future Grand Slam champion.

Those predictions were fulfilled when he won the US Open in September and became the youngest men's Grand Slam champion since Rafael Nadal won the French Open in 2005.

This year, his level has continued to accelerate and, in windy conditions at the Caja Magica, this was an example of how he can now carve out victories without being at his very best.

Against Khachanov, Alcaraz faced two break points to go 5-1 down but recovered to see them off before turning the set around.

If he defends the title at the clay-court Masters 1000 event, Alcaraz will regain the world number one ranking from Serbia's Novak Djokovic.

The world number two will face Croatia's Borna Coric in the last four after he beat Germany's Daniel Altmaier 6-3 6-3 on Wednesday night.

"I had problems in the second set, he had a lot of chances to break my serve and had his chances to win the second set," Alcaraz told Amazon Prime.

"I am very happy to get through and finish the match playing such a great level.

"This is my game to try and make different shots and make tennis different. That is my style."

What else happened in Madrid?

In the women's singles, world number one Swiatek needed just 26 minutes to win the opening set against Martic and broke the 27th seed from Croatia once more in the second to seal a commanding victory.

The two-time French Open champion, whose only defeat in her past 29 matches on the clay came last July, will compete in the Madrid semi-finals for the first time after missing last year's event through injury.

The 21-year-old from Poland will play Russia's Veronika Kudermetova in the last four.

Kudermetova, seeded 12th, reached the biggest semi-final of her career with a 6-4 0-6 6-4 win over American third seed Jessica Pegula.

Britain's Neal Skupski and his Dutch playing partner Wesley Koolhof - the top seeds in the men's doubles - lost 6-3 6-2 against India's Rohan Bopanna and Australia's Matt Ebden in their quarter-final.

Murray back to winning ways on the clay

Murray, 35, decided to play in the Aix-en-Provence event - a level below the main ATP Tour - after losing in the Monte Carlo and Madrid first rounds in April.

The Briton won 6-3 6-2 against fellow veteran Monfils, who has slipped to 322nd in the rankings after injury.

Murray, ranked 52nd in the world, plays France's Laurent Lokoli in round two.

The three-time Grand Slam champion travelled to Aix-en-Provence for some more time on the match court as he prepares for the French Open, which starts on 28 May.

Murray has played little on the clay since having career-threatening hip surgery four years ago, losing both his matches on the surface this year before this event.

After one-sided losses to Australia's Alex de Minaur in Monte Carlo and Italian qualifier Andrea Vavassori in Madrid, he earned a morale-boosting win over France's former world number six Monfils.

Murray remains focused on a return to Roland Garros for only his second appearance at the Grand Slam tournament since he reached the semi-finals in 2017.