Latvia's Ernests Gulbis, recapturing the form that helped him become one of the brighteset stars on the ATP tour a year ago, leapt 42 spots to No. 67 in the latest rankings relased on Monday ahead of Indian Wells.
Still just 24 years old, Gublis peaked at No. 21 in the world in the February of 2011, but has struggled since, dropping as far as No. 159 in the world in the fall of 2012.
But he turned all that around this past weekend at Delray Beach, winning through three rounds of qualifiers, then upsetting No. 23 Sam Querrey in the second round and No. 19 Tommy Haas in the semifinals on his way to a title, 262 points and $78,000.
It's Gulbis' second time winning Delray Beach and his first title since Los Angele in 2011 (third ATP title overall).
Gulbis was easily the top gainer on the week inside the Top 100. There were only minor moves in the Top 20 - Nicolas Almagro retook No. 11 from Marin Cilic, and Milos Raonic did likewise with No. 17, bypassing Stanislas Wawrinka.
Tumbling the other way was Spain's Fernando Verdasco, who dropped five spots to No. 29 in the world as he dropped to 2-3 on the young season.
The 29-year-old Verdasco, who peaked at No. 7 in the world in 2009 and was a constant in the Top 10 until last season, fell int he first round at San Jose to No. 105 Tim Smyczek last week, has not won a title since 2010, and reached just one final in 2012.
WTA
There was not a single move in the women's Top 20, but a new face at No. 21, where 24-year-old Carla Suarez Navarro climbed seven spots to to start the week.The diminutive (5-feet, 4-inch) Spaniard reached the Acapulco finals last week, losing the title match to No. 8 Sara Errani to gain 200 points in the rankings.
The biggest move of all in the women's Top 100 came from the Czech Republic's 20-year-old Karolina Pliskova, the surprising winer at Kuala Lumpur on Sunday.
Previously ranked 127th in the world, Pliskova rose to 84th by taking out the fourth and fifth seeds before knocking off American Bethanie-Mattek-Sands in the title match to earn 280 points and $40,000. Her first career title improved Pliskova to 11-6 on the season.