It must be a strange feeling playing someone you know almost as well as you know yourself, like hitting the ball into a mirror and watching it come back. Eddie Dibbs and Harold Solomon are friends, practice partners, former doubles parters. They are so similar in frame and game that one might say they are doubles.

How often have they played? "About a million times," said Dibbs. "We know each other's games inside and out. It's just a matter of who gets the breaks or plays better." Tonight that was Dibbs.

He beat Solomon, 3-6, 6-4, 6-3, in the feature match of the first round of the D.C. National Bank Tennis Classic at Rock Creek Tennis Stadium. The match lasted 2:07, not quite as long as the rain delay that held up the start for 2 hours 45 minutes, during which Dibbs played Pac-Man.

In the match that followed, Victor Pecci defeated fifth-seeded Andres Gomez, 3-6, 6-1, 6-3, in a match that ended with about 190 people watching at 2:11 a.m.

It could have been worse. It could have been like last year when all the first-round night matches were canceled because of rain.

For old friends Solomon and Dibbs, it has been a strange year. Solomon, who won this tournament in 1974, is ranked 88th on the Association of Tennis Professionals computer, the lowest in his career. Seven times (in 14 tournaments), he has lost in the first round. In 1980, he was ranked seventh and last year he was 22nd. "He's too good a player to be where he is now," Dibbs said, protectively. "Harold's getting some tough first-round matches. That happens when you're not seeded every week. I'm playing less than he is."

Dibbs, who is seeded seventh here, is playing in only his 12th tournament this year (he is ranked 22nd). The rustiness shows. Last week in Boston, he lost in the second round to Jim Delaney of Potomac (a first-round loser here yesterday). This week, he struggled to get by. Struggled with his friend, and his concentration.

Three times, he broke Solomon's serve first only to lose the advantage. In the first set, he broke to go up, 2-1. The break point, like the court, seemed interminably slow. It took 3 1/2 minutes. The two traded ground strokes, moon balls and then a few strokes with pace. Finally, Dibbs hit a forehand deep to Solomon's backhand. His return was short and wide. But so was Dibbs' fortune.

He seemed shaky. He saved two break points to go up, 3-1, but then Solomon broke him twice in a row and served out the set, 6-3. "It was tough to stay in a rhythm with him," Dibbs said, because of "the moon balls, the change of pace, soft balls, then angle balls."

In the second set, it appeared Dibbs might lose it altogether. Again, he broke first to go 3-1. Again, Solomon broke right back, this time to make it 3-2. He held to tie the set.

Now, Dibbs made things worse. He fell behind, 0-40, on three unforced errors. He hit a forehand winner, an ace, and pulled to deuce on a backhand cross-court shot, originally called out. Umpire Ken Slye overruled and called it good. Dibbs, who had been getting mixed results from the drop shots he was sending his friend on the base line, did it again. Solomon netted this one and it was Dibbs' advantage.

After an unforced error by Dibbs, Solomon made a rare rush and missed a forehand volley. It was Dibbs' advantage again. He won the game and the initiative when Solomon mis-hit a moon ball off the backhand. "He doesn't usually moon ball me that much," Dibbs said. Dibbs held his breath--and a 4-3 edge.

Solomon's will seemed to ebb. Perhaps he was distracted by the late-night hammering of a workman who was oblivious to the other men at work. But his forehand, which had seemed strong earlier in the set, began to wither.

Serving with Dibbs ahead, 5-4, Solomon hit a forehand wide to fall behind, 15-30. Dibbs got lucky when a cross-court backhand just made it over the net and gave him a set point. Solomon missed a first serve and, as usual, stayed on the base line. He hit a deep forehand that pulled Dibbs wide and prompted a defensive lob in return. Again, Solomon hit a deep forehand; again, Dibbs lobbed in self-defense. This time, Solomon lobbed back, a towering thing. But Dibbs was no longer on the defensive. He took the point and the set with a backhand winner down the line.

The match and the men were even at one set apiece. Just as in the second set, Dibbs broke to go up 3-1, and Solomon broke right back. Dibbs, who said "I couldn't serve all night," double-faulted to give his friend a break point.

On the next point, perhaps the best of the match, Dibbs served deep to Solomon's forehand. Twice, he came in to the net, trying to put the ball away and put his friend on the defensive. Twice, Solomon managed to lob back. The second lob was deep in the backhand corner. Dibbs ran around it and lobbed a forehand return. Solomon reciprocated with another lob. Dibbs drove the ball deep to Solomon's forehand and came in behind it. Solomon passed him with a net cord that hit the line. It was 3-2, Dibbs. But not for long.

Each man held serve to make it 4-3. On the first point of the eighth game, Solomon broke a string and seemed to come unstrung. He lost the point and got a new racket. Dibbs hit two forehand winners, giving himself triple break point. Solomon saved one of them. But Dibbs broke through finally with a backhand cross-court winner. He held serve with another definitive backhand, this one down the line.

Afterword, it was announced that Solomon would be unavailable for comment because he had a headache. He almost gave Dibbs one.

In afternoon play, 10th-seeded Pablo Arraya defeated Mike Bauer, 6-2, 6-2, and Juan Avendano beat Delaney, 6-3, 6-2. Also advancing into the second round were the 1982 NCAA singles champion, Mike Leach of Michigan, and the player he beat in that final, Brad Gilbert of Pepperdine.