"We played excellent game this year. We will strive hard to win the ODI series with Sri Lanka and end the year on a winning note," Harbhajan said in Chandigarh after launching a drug awareness campaign.
"We will not drop our guards and become relaxed but will keep trying to win matches in future," the seasoned tweaker added.
India ascended to the top of Test rankings after winning the three-match series against Sri Lanka 2-0.
The One-Day International series will begin in Rajkot on Tuesday.
Talking about splendid batting efforts of Virender Sehwag and Yuvraj Singh that helped India level the two-match Twenty20 series against Sri Lanka on Saturday, he said, "Both Veeru [Sehwag] and Yuvraj are great players. It is always a pleasure to watch Veeru and Yuvi batting."
Wishing a speedy recovery to pacer S Sreesanth, who is battling swine flu, Harbhajan said "I pray that with all our good wishes he recovers soon."
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Images: India vs Sri Lanka, 3rd Test, Day 4