Ryan Fox's quest to qualify for next month's US Open remains on track after an impressive second round at the Dutch Open on Saturday.

The top 10 players over a four-event stretch on the European Tour, including the British Masters where Fox finished ninth and the Soudal Open where he ended in a share of second, earn a spot at the US Open.

Fox sits fourth in that four-event ranking and while he will not play at the European Open next week, a solid showing in the Netherlands should be enough to clinch a berth to the third major of the year.

Those hopes of a trip to Massachusetts were buoyed after he shot a five-under 67 at the Bernardus Golf Club to move to seven-under for the tournament.

Five birdies and an eagle highlighted a round full of fireworks from Fox who moved into a tie for fifth at the halfway mark, three shots behind leader Ricardo Gouveia.

Meanwhile, fellow Kiwi golfer Steven Alker had no such fortune in his second round at the Senior PGA Championship.

Alker led the field after day one but failed to take advantage of his position on Saturday as he recorded an underwhelming one-over 72.

After landing six birdies and an eagle on Friday, Alker could only manage one under-par hole overnight; that was cancelled out by two bogeys.

However, the good news for Alker was that the rest of the field failed to make major ground on him and he lies in a tie for third, only two shots off the lead shared by Scott McCarron and Stephen Ames.

On the PGA Tour, Danny Lee shot the lowest round of the day at the Charles Schwab Challenge.

Lee vaulted 68 spots up the leaderboard on day two after shooting a scintillating six-under 64 that included eight birdies.

The round was in stark contrast than his opening effort of 73 on Friday, so the impressive performance still sees him sit six shots behind leaders Scottie Scheffler, Scott Stallings and Beau Hossler, in a tie for 23rd.