'Never seen this': Andy Murray booed after 'absurd' mid-match act

Andy Murray (pictured left) serving an underarm ace and (pictured right) Murray looking frustrated.
Andy Murray (pictured left) was booed, and cheered, after an underarm ace serve during his Indian Wells match. (Images: @TennisTV)

Andy Murray has stunned the tennis world after using the underarm serve in a match for the first time in his career during his win over Spanish star Carlos Alcaraz.

Murray battled past the Spanish teen sensation - who he has tipped as a future world No.1 - 5-7, 6-3, 6-2 in a battle that lasted more then three hours.

'KIND OF GLAD': Emma Raducanu's surprise call after brutal reality check

HEATED: Police separate Kyrgios, girlfriend amid quarantine row

Alcaraz, 18, who reached the quarter-finals of this year's US Open, initially looked awestruck by the occasion as a string of unforced errors left him trailing 3-0 and 0-40 at the start of the match.

But from the verge of a double-break down he grew in confidence, and took the first set before Murray's experience and versatility shone through.

However, the biggest talking point of the match was Murray's audacious under-arm ace straight from the Nick Kyrgios textbook.

In the second set, Alcaraz was standing deep to return Murray's first serve.

And Murray took full advantage with an underarm serve ace.

The crowd reacted with mixed emotions as some booed, while others cheered the tactic.

Fans on social media were just as divided to see the three-time grand slam champ use the controversial tactic so late in his career.

Andy Murray explains underarm serve tactic

The underarm serve has become a controversial talking point in recent years due to Aussie Kyrgios' willingness to deploy the tactic.

Last year, Murray made his position on the underarm serve tactic clear when he said it was a 'legitimate' play.

And he obviously stands by his comment after using the tactic for the first time in his illustrious career at the age of 34.

"Yeah well, I mean, he started standing further back to return the first serve and the courts are painfully slow here," Murray said, when asked about the underarm serve.

Andy Murray (pictured) thanks the crowd and celebrates his victory over Carlos Alcaraz at Indian Wells.
Andy Murray (pictured) celebrates his victory over Carlos Alcaraz of Spain in the third round of the BNP Paribas Open at Indian Wells. (Photo by TPN/Getty Images)

"I wasn't getting many free points on my first serve, I served three aces the whole match and one of them was the underarm serve.

"I was thinking about using it again the third set, but I didn't.

"But yeah, first time I've ever done it in a match and I got the ace, so maybe I'll try it again in the future."

Murray will now play Alexander Zverev in the Round of 32.

with AAP

Click here to sign up to our newsletter for all the latest and breaking stories from Australia and around the world.