India captain Virat Kohli equalled a record for consecutive successful Test series, but ended the victory over Sri Lanka with a tinge of disappointment, having drawn the third match.
Kohli's men won the three-match contest 1-0 after a crushing win in Nagpur was sandwiched by draws in Kolkata and Delhi.
Only bad light had stopped a relentless charge at Eden Gardens, but Sri Lanka's impressive resilience at the Feroz Shah Kotla Ground - anchored by Dhananjaya de Silva's 119 - prevented Kohli from signing off for 2017 with a match win.
Kohli will rest through the white-ball contests against Sri Lanka and he may spend some of the time stewing over missed chances in Delhi.
"When you're not able to finish off in the second innings after having them three down on day four is disappointing," he said.
"But they played well, they showed composure and confidence. The pitch got tired in the end. They didn't give us any chances to get into the game.
"In hindsight, if we would've grabbed our chances in the first innings, maybe they wouldn't have got so many runs. We should've done better. The slip catching and fielding, we need to work on."
Kohli will return to action when India tour South Africa next year and, after averaging 152.50 against Sri Lanka, he believes the time is right to take a step back, having seen similar absences work for Ravichandran Ashwin and Ravindra Jadeja.
The captain said: "Last time I took rest, it was difficult to handle. But my body is asking for it right now.
"The workload has been massive, I need rest. My body has taken a toll in the last couple of years.
"Right now is the perfect time to rest before the tour of South Africa."
Sri Lanka battled thick smog which saw several players fall ill, having come into the Test under something of a cloud after an innings loss in Nagpur which cost vice-captain Lahiru Thirimanne his place in the team.
Dhananjaya stepped up when it mattered most, while skipper Dinesh Chandimal scored a career-best 164 in the first innings.
"The vice-captain not playing, it was tough on both him and the team," Chandimal told reporters.
"It's a tough call but Dhananjaya and Roshen Silva [who scored an unbeaten 74 on day five] deserved their opportunities, especially Roshen who has scored more than 6,000 runs in domestic cricket.
"It's really unfortunate for Thirimanne but Dhananjaya and Roshen Silva grabbed their opportunities.
"It was a really good innings," Chandimal said of Dhananjaya.
"We had full trust in him at number three. We knew he would give us some bowling option as well and he has grabbed the opportunity with both hands."