Sri Lankan century-maker Dhananjaya de Silva warned on Wednesday that they needed early Pakistan wickets on the final day of the second Test with bad weather looming.
Tourists Pakistan, who are chasing a record 508 for victory in Galle or need to bat out three sessions for a draw, were 89-1 when bad light stopped play on day four.
Left-handed opener Imam-ul-Haq was on 46 and skipper Babar Azam on 26.
The arrival of rain confirmed a second consecutive early finish, keeping alive Pakistan's hopes of a draw — and with it victory in the two-match series, which they lead 1-0.
De Silva, who hit 109, said the hosts were wary that bad light could mean another shortened final session on Thursday.
"We need to get wickets early tomorrow," he said. "The key is to bowl at one point consistently."
The tourists will need to make an unprecedented chase — with another 419 runs needed to win — if they are to make it 2-0.
Sri Lanka, who declared their second innings on 360-8 in the second session after resuming on 176-5, need nine wickets on the final day to end the series level.
Earlier, De Silva made a dominant century before being run out at the non-striker's end and Sri Lanka skipper Dimuth Karunaratne called his batsmen back to the pavilion.
De Silva put on a key stand of 126 with overnight partner Karunaratne, a left-handed batsman who battled spasms of back pain during his knock of 61.