By SABC Sport
14th March 2024
World number 123 Nardi had stunned Novak Djokovic in round three on Tuesday but could not find the same level and went down 6-4 6-3 to the American.
Seventeenth seed Paul was able to claim crucial breaks at the end of the first and second set to keep up his fine form in 2024.
After the first eight games had stayed on serve, Paul made the most of a double-fault by lucky loser Nardi to break to go 5-4 up.
Paul, a winner in Dallas and runner-up at Delray Beach already this year, produced another break early in the second before he clinched another to secure victory in 81 minutes.
Next up for Paul is a quarter-final tie with Casper Ruud, who had to dig deep to get the better of veteran Gael Monfils.
Monfils, who beat Cameron Norrie on Monday, looked set to claim another scalp after he edged the first set.
Ruud impressively held his nerve to edge a tie-breaker and force a decider where he secured a break in the third game to take control.
There was no looking back for the Norwegian afterwards and he progressed with a 3-6 7-6 (3) 6-4 win.
Daniil Medvedev followed ninth seed Ruud into the last eight with an accomplished 6-4 6-4 victory over Grigor Dimitrov.
Medvedev, seeded fourth, sent down five aces during a rapid 77-minute win to continue his fine run in Indian Wells after he finished runner-up to Carlos Alcaraz last year.
He will face seventh seed Holger Rune, who came from a set down to beat American Taylor Fritz 2-6 7-6 (2) 6-3.