Lleyton Hewitt showed he’s still got a lot of tennis left in him as he made a successful return from retirement at the Estoril Open on Tuesday.

Partnering fellow Australian Alex De Minaur, Hewitt pulled off a 6-4 6-4 upset win over 2^nd seeds Michael Venus of New Zealand and Raven Klaasen of South Africa in the first round of the ATP 250 clay-court event in the Portuguese city.

The wildcard entrants will next square off against the British combination of Kyle Edmund and Cameron Norrie in the quarter-finals.

Hewitt, a former No. 1 and a two-time Grand Slams champion, called a time on his career in 2016. He, however, launched his comeback earlier this year, playing the doubles events at Brisbane International and the Australian Open.

And, the 37-year-old said that he’ll not be done at the end of this week as he intends to make some more doubles appearances.

“I don’t know if I ever retired from doubles,” Hewitt was quoted as saying. “I’m still competitive on the court. I don’t know what I’ll play this year, but I certainly will be playing some,” he added.