Serena Williams rallied from a set down to beat Christina McHale at the WTA Auckland Classic on Thursday, but said it was just the workout she needed.

With her focus on winning a 24th Grand Slam at the Australian Open, Williams said she needs all the court time she can get after a long off-season since losing September’s US Open final.

It took the top seed two hours to put away the 27-year-old McHale and advance to a quarter-final with Germany’s Laura Siegemund, who ousted teen prodigy Coco Gauff in the second round.

Williams was broken three times before losing the first set 3-6 but recovered to take the next two sets 6-2, 6-3 in the all-American affair.