Sri Lanka captain Dhananjaya de Silva labelled his side's triumph over England as "special" following their eight-wicket win in the final Test at The Oval.
Pathum Nissanka's unbeaten century led the tourists to victory, having started day four needing just 125 runs with nine wickets in hand.
Despite the loss of Kusal Mendis (39), Sri Lanka were able to halt their seven-match losing streak in Tests against England, claiming their first win against them since June 2014.
Nissanka's unbeaten 127 from 124 deliveries also made him only the fourth batter to log a strike rate of more than 100 when scoring a ton in men's Tests.
De Silva hailed Sri Lanka's resilience in claiming the deserved victory, believing his opening batsman is the best in the business for the Lions.
"It is very special, winning in England. The boys were tough enough to handle the pressure and get into some scenarios," De Silva told BBC Sport.
"It is not comfortable. There was hard work put in by the bowlers and batters. We were there in every match - had positive points. The boys wanted to win in the end.
"Credit to all of the bowlers. They have been on target from ball one. In the second innings, they were spot on.
"He [Nissanka] was in form the last couple of years and doing well in white-ball format. He has proved he is the best opener in Sri Lanka right now."
Kamindu Mendis, who struck 113 from 183 deliveries in the Lions' five-wicket defeat in the first Test, was handed Sri Lanka's Player of the Series after the triumph.
Mendis was consistent with the bat throughout the series, scoring 267 runs across the five innings he was in at the crease.
"It's a good win in these conditions. We did really well, especially the seamers and the batters did really well today," Mendis said.
"In these conditions, you have to face very difficult situations but I just wanted to enjoy it. That's it.
"I just made small changes, not big ones. It's a big deal but you have to be confident in your ability and enjoy your game.
"It's always a challenge facing seamers in England."
Sri Lanka's attentions will now turn to a two-match Test series on home soil against New Zealand, starting on September 18 at the Galle International Stadium.