Thompson battles on in three sets against Harris
The four-time ATP Tour titlist defeated Alexei Popyrin 7-6(4), 6-3 after one hour and 15 minutes to reach the second round. The 31-year-old American is competing at this ATP 250 for the fourth time, and it is the third time he has made it through his opener.
Johnson hit 12 aces and did not face a break point against his 21-year-old opponent in their first ATP Head2Head clash. The World No. 80 will next play fifth seed Taylor Fritz or Russian qualifier Evgeny Donskoy.
Another American who advanced on the first day of main draw action was qualifer Bjorn Fratangelo, who eliminated 37-year-old Italian Andreas Seppi 7-5, 7-6(5). The World No. 190 will challenge fourth seed Reilly Opelka, also from the United States, for a spot in the quarter-finals.