PGA Tour rookie Wyndham Clark will be chased by a pair of superstars in Vijay Singh and Rickie Fowler on Sunday at the Honda Classic. Here’s where things stand through 54 holes at PGA National: 

Leaderboard: Clark (-7), Singh (-6), Kyoung-Hoon Lee (-6), Keith Mitchell (-6), Fowler (-5)

What it means: Clark is making his 11th start of the season, playing out of the Web.com reshuffle. He is one week removed from his best finish to date, a T-10 in Puerto Rico. He racked up four top-10s on the Web last year, with a second and a third in back-to-back starts last spring, en route a 25th-place finish on the money list. Singh, 56, seeks to be the oldest winner in the history of the PGA Tour, eclipsing Sam Snead by four years. The 34-time victor hasn’t hoisted a PGA Tour trophy since 2008 but did win three times last year on PGA Tour Champions, claiming his first over-50 major at the Senior Players. Fowler was the 2017 Honda champ who is now looking for his second win in three starts, following his ugly-but-effective Super Bowl Sunday in Scottsdale. A pair of major champions, Brooks Koepka and Sergio Garcia, lurk three and four shots back, respectively.

Round of the day: Just 1 under par through two days, Singh jumped up 30 spots into a tie for second on the strength of a 5-under 65, Saturday’s best score by one. The Big Fijian birdied four of his first eight holes before dropping his only shot at the par-4 ninth to make the turn in 32. He added two more birdies at No. 15 and 18 for a bogey-free, back-side 33.

Best of the rest: Five players — Fowler, Michael Thompson, Kramer Hickock, Gary Woodland and Roger Sloan — signed for 66. Fowler’s Saturday scorecard featured five circles and a single square, at the par-3 15th.

Biggest disappointment: One of the two 36-hole co-leaders, Sungjae Im plummeted 50 spots on the leaderboard with a 7-over 77. Im doubled the second and added five more bogeys in a birdie-free round. He’ll start Sunday eight back, 1 over for the week.

Rules violation of the day: Adam Schenk on Saturday was retroactively assessed a two-stroke penalty for a caddie-alignment violation on Friday. His second-round, 1-under-par 69 became a 1-over-par 71.

Ducks of the day: