Portobello came into the match with much to prove after losing their opening encounter at West Lothian by a hefty 25 shots while Midlothian arrived with spirits high after scoring a 19-shot away victory over Tweedbank.
Despite wins on two rinks – skipped by Ronnie Douglas and Davy McLeod – there were losses for Ian Paterson and Tony McLaren who were sunk by Frank Gray and George Cairns.
Cairns skipped Willie Gilroy, Billy Dunn and Rab Stewart to an emphatic 26-6 victory over several times club champion Tony McLaren and his front three of John Moodie, Jack McLeod and Jim Glasgow who were torpedoed 17-0 over eight ends.
The Midlothian effort was further buoyed Gray who produced a dominant performance to skip Willie Clelland, Norrie Anderson, and Jim Harrower to a 17-12 win over Eddie Romany, Gordon McCathie, Keith Young and Paterson.
Douglas brought a breath of fresh air to the Portobello challenge with a whirlwind start to lead 14-3 after seven ends then did enough to skip Ron Stewart, Steve McVeigh and Alex Walker to a 20-10 win over Alex Greig.
Greig and his rink of Alex Grant, George McGauley and Willie Burnett only lost the end count 9-8 but heftier scoring by the opposition included two 3s and a mighty 5.
McLeod also made a bright start for Porty to skip Tom Ronald, Rob Robertson and John Fraser into a 13-4 lead then onto a 16-11 win over John Mair, John Connolly, Bob Campbell and Alex Cox.
“My bowls are now in the Forth estuary!” said McLaren later.
West Lothian Seniors, meanwhile, won at home against a Balbardie team who had impressed with an opening 26-shot win over East Lothian.
Despite suffering double figure losses on two rinks the home team from Livingston managed to bank the two points with a thrilling 58-52 victory over their Bathgate neighbours.
The telling moment was made by the rink of Davie Anderson, George Rarity, Brian Holloran and George Marshall who crushed Alex Morton, Jimmy Clark, Jim Fraser and Andrew McKinnon 26-4.
The Marshall triumph was supported by a 17-13 win for Alistair Lindsay Stuart Orr Raymond McMahon and Jack Morton who recovered from 10-1 down to Mel Forde, George Charleston, Ritchie Templeton and Hugh Marshall.
East Lothian beat Bainfield 71-45; Teviotdale lost at home to Tweedbank 52-71.