Mickelson finished tied with Rory McIlroy for second place, one stroke behind Pablo Larrazabal, at the European Tour's Abu Dhabi HSBC Golf Championship. That moves Mickelson ahead of Justin Rose and into fourth place in the world rankings.
Day passes Sergio Garcia to get back into the Top 10. Garcia tied for 19th at Abu Dhabi, which drops him back in the rankings.
McIlroy edges very close to No. 6-ranked Zach Johnson but remains seventh this week.
Larrazabal picked up his third European Tour title in the Abu Dhabi tournament, although it was his first win since June 2011. He goes from 103rd to 53rd in the world rankings.
Patrick Reed jumps 28 spots to No. 41 after his win at the PGA Tour's Humana Challenge. It was his second PGA victory, coming five months after he won the Wyndham Championship.
Tiger Woods marks his 667th week as the world's No. 1-ranked golfer. He opens his 2014 schedule at the PGA's Farmers Insurance Open in La Jolla, Calif.
The European Tour continues its desert swing with the Commercialbank Qatar Masters.
The men's world golf rankings Top 10, listing player's name, home country and ranking points average:
1. Tiger Woods, United States, 11.05
2. Adam Scott, Australia, 9.06
3. Henrik Stenson, Sweden, 8.85
4. Phil Mickelson, United States, 7.16
5. Justin Rose, England, 6.77
6. Zach Johnson, United States, 6.42
7. Rory McIlroy, Northern Ireland, 6.40
8. Matt Kuchar, United States, 6.08
9. Steve Stricker, United States, 5.42
10. Jason Day, Australian, 5.08