Lleyton Hewitt’s remarkable run at Queen’s Club continued as he toppled Argentine third seed Juan Martin del Potro to book an unlikely semi-final appearance.

Hewitt, a four-time champion at the grass-court event, upset the world No.8 6-2 2-6 6-2 on Friday to reach the tournament’s last four for the first time since he last won the title in 2006.

Del Petro is the highest-ranked player Hewitt has beaten since he beat then-world No.2 Roger Federer to win his last ATP title at Halle in 2010.

Hewitt, 32, came in to this week’s event on the back of a stop-start season and simply hoping to build confidence and court time ahead of Wimbledon, where he is the 2002 champion.

But a first ATP title in three years is not out of the question based on a string of impressive performances.

The Australian world No.82 will next face Croatian fifth seed Marin Cilic, who defeated second seed Tomas Berdych 7-5 7-6 (7-4) earlier on Friday.

Having impressed in victories over seeded players Grigor Dimitrov and Sam Querrey, Hewitt carried over his form into a superb first-set performance on Friday.

Both players served well early, but two double faults from Del Potro allowed Hewitt to break to go 4-2 up and he raced away with the first set.

Del Potro hit straight back early in the second set, breaking twice as errors crept into Hewitt’s game and the match was quickly back on level terms.

But Hewitt rediscovered his serving rhythm early in the deciding set before breaking Del Petro to love to go 3-1 up.

From there he didn’t let up, breaking serve again to claim victory.

He converted his first match point with a pin-point forehand volley before celebrating with his son Cruz on court.