That was followed by two other tight matches, 17-15 against an inexperienced St Heliers pair of Paul Renwick and Richard Kempthorne, who came close to causing a major upset after suffering a 31-8 hammering in the opening round from Birkenhead greenkeeper Dennis Matthews and Keith Burgess, and then 21-19 over the pair skipped by Carlton-Cornwall stalwart John Carruthers.
Lawson, though, slightly rusty after having to prepare on earthquake-affected greens at his Canterbury base, welcomed the tightness of all his games. "It gets you into a good groove," he said.
Lawson was at his effective best against Vlahovic, the 1996 national singles champion who is now back bowling on Australia's Gold Coast after many years away from the game. He drew the winning shot on the extra end, after earlier saving a four which could have seen Vlahovic away to a 19-10 lead.
Upsets were frequent yesterday in both the men's pairs and the women's singles qualifying because of the difficult blustery conditions.
Internationals Richard Girvan and Danny Delany were among the prominent first round losers, though they came up against high-profile opponents in former Black Jack Jamie Hill and his father, Neville, the Hills winning 16-10.
Girvan and Delany recovered to win their next two games and should qualify today. Another former national titleholder Petar Sain and his Auckland lead Scott Cottrell suffered two losses and so cannot afford another today. But among the winners were Shannon McIlroy and Matt Gallop and the 2009 champions, Rob Ashton and Ray Boffa.
The casualties in the women's singles, where three games were needed from yesterday's four rounds to make the post-section, included recent New Zealand player Genevieve Baildon and Jo Babich, a double national champion in 2008.
Mandy Boyd, Anne Bateman, Reen Stratford and Clare McCaul, who thumped Babich 21-6, were among top players to suffer an early loss, but two who were impressive in sweeping through their opening three matches were Wellington's Kaaren Guilford and Northlander Sue Wightman.
Guilford was runner-up last month in the Auckland Open at Henderson, while Wightman was the national singles champion in Auckland in 2009.