Scotland players need to maintain the levels shown in this year's dramatic Twickenham fight back if they are to have a chance of British and Irish Lions selection, says Scott Hastings.
Warren Gatland will lead the tourists for a third successive time when they travel to South Africa in 2021.
The Wales head coach did not start a single Scot in the 2013 and 2017 Tests.
"The reason he has not picked Scotland players is that they have not delivered," said former Lion Hastings.
"They have not performed on a consistent enough basis to merit selection.
"The last time we saw the desired level of intensity was in the second 40 minutes against England. If Scotland can reach those intensities, then Scotland will have players on the Lions tour."
Scotland recovered from 31-0 down against England to earn a remarkable 38-38 Six Nations draw in March. However, Gregor Townsend's men managed just one victory in this year's tournament, finishing 14 points behind Gatland's Grand Slam winners.
"There is a great opportunity for Scottish players now and I hope a number of these guys really stand up over the next couple of years," said former Scotland centre Hastings, who toured with the Lions in 1989 and 1993.
"They need to perform in the Pro14 and the European stage and be on the top of their game against their opposite numbers in the Six Nations. These are the people you are competing with for places."
Gatland oversaw a winning tour of Australia in 2013 and a drawn series in New Zealand four years later.
There were three Scots - Richie Gray, Stuart Hogg and Sean Maitland - in his original squad for 2013, with lock Gray appearing as a 67th-minute replacement in the final Test. In 2017, there were two Scots - Hogg and Tommy Seymour - in the original squad, with Greig Laidlaw added as a pre-tour replacement, but none were involved in the Tests.
Hastings described Gatland as a "hand in glove fit" for the job and thinks the New Zealander may well have a role in mind for Townsend in South Africa.
Townsend turned down an offer to be part of the Lions' coaching team in 2017 since it clashed with him taking over in time for Scotland's summer tour.
Hastings believes the Scotland head coach will be "on the radar", saying: "The beauty of rugby is it's all about blends. Who are the innovators? Who does Warren want to have as part of his team? I'm sure Gregor will be part of that thinking."